Pub Date : 2026-02-04DOI: 10.1016/j.jbc.2026.111243
Kris Dammen-Brower, Stanley Zhu, Christian Agatemor, Safiya Aafreen, Vrinda Dharharma, Christopher T Saeui, Hui Li, Jian Song, Matthew J Buettner, Keith R Kwagala, Hui Zhang, Howard E Katz, Guanshu Liu, Kevin J Yarema
Profiling the secretome for biomarkers offers an attractive, minimally invasive strategy to detect and monitor cancer. Several challenges, however, must be overcome including the broad dynamic range of biomolecules in the secretome and the requirement for selective detection of tumor-associated markers. Here, we employed a metabolic glycoengineering (MGE) strategy, using 1,3,4-O-Bu3ManNAz, an azido-tagged, bioorthogonal metabolic precursor of sialic acid, to label the glycome of pancreatic near-normal and cancer cells to improve conventional LC-MS/MS proteomics-based biomarker discovery. By using this "MGE-LC-MS/MS" approach that incorporates MGE-enrichment into conventional LC-MS/MS proteomics, we identified several unique proteins from the secretomes of cancer cells evaluated in vitro. In addition to proteins known to be secreted, we identified several putatively intracellular, non-N-glycosylated proteins such β-glucocerebrosidase and paladin linked to pancreatic cancer (PC) as well as proteins associated with extracellular vesicles (EV) in PC such as DCTPP1. The identification of EV-associated proteins was consistent with our discovery that ManNAc analogs used in the MGE-LC-MS/MS workflow enhance EV production, creating a more complete secretome profile of PC cells. Pointing towards clinical relevance, we used MGE-LC-MS/MS to enrich PC-derived glycoproteins from plasma harvested from mice bearing xenografted human pancreatic tumors, unambiguously demonstrating that this approach can interrogate the secretomes of cancer cells for biomarker discovery. Finally, we discovered that MGE dramatically improved the production of EVs, which both aids in biomarker discovery (this study) and holds potential to facilitate biomanufacturing of these nascent drugs.
{"title":"Profiling the Pancreatic Cancer Secretome with Metabolic Glycoengineering.","authors":"Kris Dammen-Brower, Stanley Zhu, Christian Agatemor, Safiya Aafreen, Vrinda Dharharma, Christopher T Saeui, Hui Li, Jian Song, Matthew J Buettner, Keith R Kwagala, Hui Zhang, Howard E Katz, Guanshu Liu, Kevin J Yarema","doi":"10.1016/j.jbc.2026.111243","DOIUrl":"https://doi.org/10.1016/j.jbc.2026.111243","url":null,"abstract":"<p><p>Profiling the secretome for biomarkers offers an attractive, minimally invasive strategy to detect and monitor cancer. Several challenges, however, must be overcome including the broad dynamic range of biomolecules in the secretome and the requirement for selective detection of tumor-associated markers. Here, we employed a metabolic glycoengineering (MGE) strategy, using 1,3,4-O-Bu<sub>3</sub>ManNAz, an azido-tagged, bioorthogonal metabolic precursor of sialic acid, to label the glycome of pancreatic near-normal and cancer cells to improve conventional LC-MS/MS proteomics-based biomarker discovery. By using this \"MGE-LC-MS/MS\" approach that incorporates MGE-enrichment into conventional LC-MS/MS proteomics, we identified several unique proteins from the secretomes of cancer cells evaluated in vitro. In addition to proteins known to be secreted, we identified several putatively intracellular, non-N-glycosylated proteins such β-glucocerebrosidase and paladin linked to pancreatic cancer (PC) as well as proteins associated with extracellular vesicles (EV) in PC such as DCTPP1. The identification of EV-associated proteins was consistent with our discovery that ManNAc analogs used in the MGE-LC-MS/MS workflow enhance EV production, creating a more complete secretome profile of PC cells. Pointing towards clinical relevance, we used MGE-LC-MS/MS to enrich PC-derived glycoproteins from plasma harvested from mice bearing xenografted human pancreatic tumors, unambiguously demonstrating that this approach can interrogate the secretomes of cancer cells for biomarker discovery. Finally, we discovered that MGE dramatically improved the production of EVs, which both aids in biomarker discovery (this study) and holds potential to facilitate biomanufacturing of these nascent drugs.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"111243"},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146131915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.jbc.2026.111240
Dongsheng Xing, Hongwei Cao, Yan Yang, Shengyang Liu, Hanbing Yu, Zhenyu Liu, Kunrong Wang, Xin Wei, Aihui Yan
Tristetraprolin (TTP), which encodes an RNA-binding protein, was identified as a biomarker in three types of IgE-driven allergic tissues. Remarkably, in the nasal mucosa of the ragweed pollen-induced AR mouse model, TTP mRNA levels were increased approximately threefold. TTP overexpression in AR mice alleviated nasal inflammation and epithelial barrier damage, accompanied by reduced frequency of nasal spray and nasal friction, eosinophils/neutrophils/macrophages/goblet cells infiltration, and Th2 cytokines interleukin (IL)-4, IL-5, and IL-13 secretion. The impact of TTP on the activation and differentiation of Th2 cells was assessed by utilizing naïve CD4 T cells isolated from mice. We found that TTP significantly suppressed Th2 activation and differentiation, as evidenced by the decreased levels of cytokines and the percentage of Th2. Transcriptomic profiling of CD4+ T cells (with/without TTP overexpression) was analyzed, and 14 down-regulated genes containing AU-rich elements (AREs) were obtained. The study concentrated on downregulated E3 ubiquitin ligase tripartite motif 18 (TRIM18) in TTP-overexpressed CD4+ T cells. Specifically, TTP protein bound to the ARE located at positions +3640 to +3644 (5'-UAUUU-3') within the 3'UTR of mouse TRIM18, and this interaction reduces TRIM18 mRNA stability, a process that depends on the active-site residue Cys-139 within the second CCCH-type zinc finger motif of TTP. TRIM18 overexpression weakened the effects in CD4+ T cells induced by TTP overexpression. Collectively, TTP suppresses Th2 activation and differentiation in AR by modulating TRIM18 mRNA stability, highlighting their interaction as a critical pathway in allergic inflammation.
{"title":"RNA-binding protein tristetraprolin inhibits Th2 cell activation and differentiation in allergic rhinitis by promoting TRIM18 mRNA decay.","authors":"Dongsheng Xing, Hongwei Cao, Yan Yang, Shengyang Liu, Hanbing Yu, Zhenyu Liu, Kunrong Wang, Xin Wei, Aihui Yan","doi":"10.1016/j.jbc.2026.111240","DOIUrl":"https://doi.org/10.1016/j.jbc.2026.111240","url":null,"abstract":"<p><p>Tristetraprolin (TTP), which encodes an RNA-binding protein, was identified as a biomarker in three types of IgE-driven allergic tissues. Remarkably, in the nasal mucosa of the ragweed pollen-induced AR mouse model, TTP mRNA levels were increased approximately threefold. TTP overexpression in AR mice alleviated nasal inflammation and epithelial barrier damage, accompanied by reduced frequency of nasal spray and nasal friction, eosinophils/neutrophils/macrophages/goblet cells infiltration, and Th2 cytokines interleukin (IL)-4, IL-5, and IL-13 secretion. The impact of TTP on the activation and differentiation of Th2 cells was assessed by utilizing naïve CD4 T cells isolated from mice. We found that TTP significantly suppressed Th2 activation and differentiation, as evidenced by the decreased levels of cytokines and the percentage of Th2. Transcriptomic profiling of CD4+ T cells (with/without TTP overexpression) was analyzed, and 14 down-regulated genes containing AU-rich elements (AREs) were obtained. The study concentrated on downregulated E3 ubiquitin ligase tripartite motif 18 (TRIM18) in TTP-overexpressed CD4+ T cells. Specifically, TTP protein bound to the ARE located at positions +3640 to +3644 (5'-UAUUU-3') within the 3'UTR of mouse TRIM18, and this interaction reduces TRIM18 mRNA stability, a process that depends on the active-site residue Cys-139 within the second CCCH-type zinc finger motif of TTP. TRIM18 overexpression weakened the effects in CD4+ T cells induced by TTP overexpression. Collectively, TTP suppresses Th2 activation and differentiation in AR by modulating TRIM18 mRNA stability, highlighting their interaction as a critical pathway in allergic inflammation.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"111240"},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146131954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.jbc.2026.111245
Eleanor E Bashian, James C Paulson, Peng Wu
The development of therapies that boost anti-tumor immunity has transformed cancer treatment. While the efficacy of traditional therapies, such as chemotherapy and radiation therapy, is limited by toxicity and resistance, forms of immunotherapy, including immune checkpoint blockade therapies and engineered cellular therapies, have shown unprecedented success for certain patient populations. Despite these advances, therapeutic resistance remains a significant barrier, and alternative therapies are needed to overcome immune evasion mechanisms. One prominent evasive mechanism utilized by tumor cells is hypersialylation, the overexpression of glycans capped with sialic acid on the cell surface. This review focuses on the immunosuppressive role of sialic acid in cancer and highlights opportunities to target sialic acid and its binding proteins, offering a promising therapeutic perspective to counteract resistance and improve patient outcomes.
{"title":"Sialic acids modulate immune responses in cancer: Therapeutic opportunities.","authors":"Eleanor E Bashian, James C Paulson, Peng Wu","doi":"10.1016/j.jbc.2026.111245","DOIUrl":"https://doi.org/10.1016/j.jbc.2026.111245","url":null,"abstract":"<p><p>The development of therapies that boost anti-tumor immunity has transformed cancer treatment. While the efficacy of traditional therapies, such as chemotherapy and radiation therapy, is limited by toxicity and resistance, forms of immunotherapy, including immune checkpoint blockade therapies and engineered cellular therapies, have shown unprecedented success for certain patient populations. Despite these advances, therapeutic resistance remains a significant barrier, and alternative therapies are needed to overcome immune evasion mechanisms. One prominent evasive mechanism utilized by tumor cells is hypersialylation, the overexpression of glycans capped with sialic acid on the cell surface. This review focuses on the immunosuppressive role of sialic acid in cancer and highlights opportunities to target sialic acid and its binding proteins, offering a promising therapeutic perspective to counteract resistance and improve patient outcomes.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"111245"},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146131969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Porcine enteric coronaviruses, including transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhea virus (PEDV), swine acute diarrhea syndrome coronavirus (SADS-CoV), and porcine deltacoronavirus (PDCoV), cause severe watery diarrhea, vomiting, dehydration, and high mortality in piglets, leading to enormous economic losses in the swine industry worldwide. They have the capability to infect a variety of cell lines from pigs, humans, and other animals, with high risks of interspecies transmission and potential threats to public health. These viruses employ their spike glycoproteins to engage with various receptors, coreceptors, cofactors, and other host factors that further mediate membrane fusion to accomplish the entry process. This review summarizes the recent findings regarding the pathways, receptors, coreceptors, cofactors, and other host factors utilized by TGEV, PEDV, SADS-CoV, and PDCoV for cellular entry. Several important targets for antiviral therapeutics and some key aspects of the entry process for these viruses that await discovery are highlighted. A comprehensive understanding of the entry mechanisms of porcine enteric coronaviruses will provide new insight into the development of novel antiviral therapeutic strategies.
{"title":"Cell entry mechanisms of porcine enteric coronaviruses.","authors":"Yiping Wang, Fei Zhao, Qin Zhao, Senyan Du, Yiping Wen, Rui Wu, Sanjie Cao, Feng Cong, Xiaobo Huang","doi":"10.1016/j.jbc.2026.111250","DOIUrl":"https://doi.org/10.1016/j.jbc.2026.111250","url":null,"abstract":"<p><p>Porcine enteric coronaviruses, including transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhea virus (PEDV), swine acute diarrhea syndrome coronavirus (SADS-CoV), and porcine deltacoronavirus (PDCoV), cause severe watery diarrhea, vomiting, dehydration, and high mortality in piglets, leading to enormous economic losses in the swine industry worldwide. They have the capability to infect a variety of cell lines from pigs, humans, and other animals, with high risks of interspecies transmission and potential threats to public health. These viruses employ their spike glycoproteins to engage with various receptors, coreceptors, cofactors, and other host factors that further mediate membrane fusion to accomplish the entry process. This review summarizes the recent findings regarding the pathways, receptors, coreceptors, cofactors, and other host factors utilized by TGEV, PEDV, SADS-CoV, and PDCoV for cellular entry. Several important targets for antiviral therapeutics and some key aspects of the entry process for these viruses that await discovery are highlighted. A comprehensive understanding of the entry mechanisms of porcine enteric coronaviruses will provide new insight into the development of novel antiviral therapeutic strategies.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"111250"},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146131971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the post-pandemic era, the persistent threat of coronaviruses demands broad-spectrum antiviral therapeutic strategies. The SARS-CoV-2 nucleocapsid protein (N protein), an essential factor for genome packaging and immune modulation, poses a promising antiviral target. Here, we determined the crystal structure of the DNA aptamer A58-T10 in complex with the N-terminal domain of the N protein (N-NTD). A58-T10 binds to the N-NTD via a unique three-tiered stem-loop that interacts with the nucleic acid-binding site of N-NTD through extensive hydrogen bonding and stacking. Structural analysis reveals that A58 contains two stem-loops with octanucleotide motifs (5'-11ACCGGATT19-3' and 5'-26ATCGGATT33-3') that specifically recognize N-NTD. Functionally, A58 inhibits N-NTD's binding to viral RNA, disrupting N protein-host cell interactions involved in immune responses. Notably, A58 exhibits broad-spectrum binding activity against N proteins from SARS-CoV-2 variants and related sarbecoviruses. These findings elucidate the specific interaction mechanism between A58 and N-NTD, highlighting its potential as an anti-sarbecovirus agent. RUNNING TITLE: Crystal structure of DNA aptamer in complex with N-NTD.
{"title":"Structural Basis of DNA Aptamer A58 Targeting the N-terminal Domain of Sarbecoviruses Nucleocapsid Protein.","authors":"Xiaoxue Chen, Suhua He, Shaojie Xue, Yuhang Luo, Zhizhong Lu, Shuang Zhu, Zhichao Miao, Shoudeng Chen, Lin Huang","doi":"10.1016/j.jbc.2026.111233","DOIUrl":"https://doi.org/10.1016/j.jbc.2026.111233","url":null,"abstract":"<p><p>In the post-pandemic era, the persistent threat of coronaviruses demands broad-spectrum antiviral therapeutic strategies. The SARS-CoV-2 nucleocapsid protein (N protein), an essential factor for genome packaging and immune modulation, poses a promising antiviral target. Here, we determined the crystal structure of the DNA aptamer A58-T10 in complex with the N-terminal domain of the N protein (N-NTD). A58-T10 binds to the N-NTD via a unique three-tiered stem-loop that interacts with the nucleic acid-binding site of N-NTD through extensive hydrogen bonding and stacking. Structural analysis reveals that A58 contains two stem-loops with octanucleotide motifs (5'-<sub>11</sub>ACCGGATT<sub>19</sub>-3' and 5'-<sub>26</sub>ATCGGATT<sub>33</sub>-3') that specifically recognize N-NTD. Functionally, A58 inhibits N-NTD's binding to viral RNA, disrupting N protein-host cell interactions involved in immune responses. Notably, A58 exhibits broad-spectrum binding activity against N proteins from SARS-CoV-2 variants and related sarbecoviruses. These findings elucidate the specific interaction mechanism between A58 and N-NTD, highlighting its potential as an anti-sarbecovirus agent. RUNNING TITLE: Crystal structure of DNA aptamer in complex with N-NTD.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"111233"},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146131991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.jbc.2026.111251
M Valenzuela-Cardenas, T S Nowicki
Tumor Necrosis Factor Alpha (TNF-α) is a pleiotropic cytokine that can both facilitate tumor progression and directly mediate tumor cell killing. This dual role creates a conundrum in which TNF can be either beneficial or detrimental for a tumor, depending on the context. Herein we describe the history of the cytokine, the cases in which TNF-α has been considered as a cancer immunotherapy, and the toxicities that can manifest from its use. We also add context to its activity, particularly in T cells (via the engagement of TNF receptors), as well as the epigenetic and immunoregulatory pathways that are elicited. Furthermore, we highlight the fundamental differences in the transcriptional and translational regulation of this cytokine, which plays a significant role in the context of malignancy and potential success of immunotherapies. This review aims to provide insight and background on molecular switches, cellular context, and TNF receptor dynamics that determine TNF-α's role as both tumor suppressor and promoter in different models, which is essential for deriving maximal benefit from TNF therapies.
{"title":"TNF-alpha: Roles in Pathogenesis and Therapeutics in Cancer.","authors":"M Valenzuela-Cardenas, T S Nowicki","doi":"10.1016/j.jbc.2026.111251","DOIUrl":"https://doi.org/10.1016/j.jbc.2026.111251","url":null,"abstract":"<p><p>Tumor Necrosis Factor Alpha (TNF-α) is a pleiotropic cytokine that can both facilitate tumor progression and directly mediate tumor cell killing. This dual role creates a conundrum in which TNF can be either beneficial or detrimental for a tumor, depending on the context. Herein we describe the history of the cytokine, the cases in which TNF-α has been considered as a cancer immunotherapy, and the toxicities that can manifest from its use. We also add context to its activity, particularly in T cells (via the engagement of TNF receptors), as well as the epigenetic and immunoregulatory pathways that are elicited. Furthermore, we highlight the fundamental differences in the transcriptional and translational regulation of this cytokine, which plays a significant role in the context of malignancy and potential success of immunotherapies. This review aims to provide insight and background on molecular switches, cellular context, and TNF receptor dynamics that determine TNF-α's role as both tumor suppressor and promoter in different models, which is essential for deriving maximal benefit from TNF therapies.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"111251"},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146131996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.jbc.2026.111230
Juno Lee, Yoonseok Choi, Taehyeong Kim, Jihoon Kim, Pahn-Shick Chang
Lipase regioselectivity (sn-1(3) vs sn-2) is crucial for synthesizing structured lipids, but the structural basis for contrasting regioselectivities in lipases with acyl-binding tunnel remains incomplete. While the correlation between a narrow tunnel entrance and sn-2 regioselectivity has been previously established, the regioselectivity of Ophiostoma piceae sterol esterase (OPE), a lipolytic enzyme with a uniquely wide tunnel entrance, remained unclear. In this study, the chiral-phase resolution of oleic species confirmed that OPE exhibits a notable sn-1(3) regioselectivity (85.8%) against trioleoylglycerol (TOG), in contrast to Candida antarctica lipase A, which possesses narrow tunnel entrance (sn-2 regioselectivity: 79.8%). Molecular dynamics simulation showed that the wide tunnel entrance of OPE facilitates stable interaction of the scissile ester group within the catalytic center only when adopting sn-1(3) binding mode; the additional C1(3)-C2 glycerol backbone linkage within TAG allows non-scissile chains to stably reside within the tunnel entrance without disrupting the interactions at the catalytic center. Overall, the results indicated that the tunnel architecture directly dictates the sn-1(3) regioselectivity of OPE, providing structural insights into the tunnel morphology-regioselectivity relationship for lipases with acyl-binding tunnel.
脂肪酶的区域选择性(sn-1(3) vs sn-2)对于合成结构化脂质至关重要,但是对比脂肪酶与酰基结合通道的区域选择性的结构基础仍然不完整。虽然狭窄的通道入口与sn-2区域选择性之间的相关性已经被建立,但具有独特的宽通道入口的脂溶酶Ophiostoma piceae固醇酯酶(OPE)的区域选择性仍然不清楚。在本研究中,油类物种的手性相分辨证实,OPE对三油基甘油(TOG)具有显著的sn1(3)区选择性(85.8%),而Candida antarctica脂肪酶a具有狭窄的隧道入口(sn2)区选择性:79.8%)。分子动力学模拟表明,只有采用sn-1(3)结合模式时,OPE的宽通道入口才有利于催化中心内可剪切酯基的稳定相互作用;TAG中额外的C1(3)-C2甘油主链允许非剪切链稳定地驻留在隧道入口,而不会破坏催化中心的相互作用。总的来说,结果表明,隧道结构直接决定了OPE的sn-1(3)区域选择性,为脂肪酶与酰基结合隧道的隧道形态-区域选择性关系提供了结构见解。
{"title":"Unraveling the regioselectivity of Ophiostoma piceae sterol esterase as a case study for lipases with wide acyl-binding tunnel entrances.","authors":"Juno Lee, Yoonseok Choi, Taehyeong Kim, Jihoon Kim, Pahn-Shick Chang","doi":"10.1016/j.jbc.2026.111230","DOIUrl":"https://doi.org/10.1016/j.jbc.2026.111230","url":null,"abstract":"<p><p>Lipase regioselectivity (sn-1(3) vs sn-2) is crucial for synthesizing structured lipids, but the structural basis for contrasting regioselectivities in lipases with acyl-binding tunnel remains incomplete. While the correlation between a narrow tunnel entrance and sn-2 regioselectivity has been previously established, the regioselectivity of Ophiostoma piceae sterol esterase (OPE), a lipolytic enzyme with a uniquely wide tunnel entrance, remained unclear. In this study, the chiral-phase resolution of oleic species confirmed that OPE exhibits a notable sn-1(3) regioselectivity (85.8%) against trioleoylglycerol (TOG), in contrast to Candida antarctica lipase A, which possesses narrow tunnel entrance (sn-2 regioselectivity: 79.8%). Molecular dynamics simulation showed that the wide tunnel entrance of OPE facilitates stable interaction of the scissile ester group within the catalytic center only when adopting sn-1(3) binding mode; the additional C1(3)-C2 glycerol backbone linkage within TAG allows non-scissile chains to stably reside within the tunnel entrance without disrupting the interactions at the catalytic center. Overall, the results indicated that the tunnel architecture directly dictates the sn-1(3) regioselectivity of OPE, providing structural insights into the tunnel morphology-regioselectivity relationship for lipases with acyl-binding tunnel.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"111230"},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146132032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.jbc.2026.111235
Mari Kurotobi, Shin-Ichiro Yamaguchi, Hiroto Koyama, Kengo Kinoshita, Masafumi Nakayama
Scavenger receptor class B type 1 (SR-B1), best known as a high-density lipoprotein (HDL) receptor, is now recognized as a multi-ligand membrane receptor. In addition to HDL, SR-B1 binds low-density lipoprotein (LDL), hepatitis C virus, Gram-positive and Gram-negative bacteria, and inorganic silica particles. However, the mechanisms by which SR-B1 recognizes diverse ligands remain unclear. We previously reported that a basic amino acid cluster consisting of K151, K156, and K395 at the extracellular apex of SR-B1 is essential for charge-dependent binding to silica and is distinct from the known HDL-binding site. In this study, homology modeling of SR-B1 revealed the HDL-binding site is oriented toward the basic cluster. Site-directed mutagenesis demonstrated that this basic cluster is required for HDL and, to a lesser extent, LDL binding, which in turn promotes binding to silica nanoparticles. The selective binding of SR-B1 to silica nanoparticles, but not to TiO2 nanoparticles, latex nanoparticles, monosodium urate crystals, or multiwalled carbon nanotubes, depends on specific HDL- or LDL-silica interactions. These findings suggest that HDL, and potentially LDL, may underlie SR-B1's function as a muti-ligand membrane receptor.
{"title":"High-density lipoprotein mediates silica nanoparticle recognition by the multi-ligand receptor SR-B1.","authors":"Mari Kurotobi, Shin-Ichiro Yamaguchi, Hiroto Koyama, Kengo Kinoshita, Masafumi Nakayama","doi":"10.1016/j.jbc.2026.111235","DOIUrl":"https://doi.org/10.1016/j.jbc.2026.111235","url":null,"abstract":"<p><p>Scavenger receptor class B type 1 (SR-B1), best known as a high-density lipoprotein (HDL) receptor, is now recognized as a multi-ligand membrane receptor. In addition to HDL, SR-B1 binds low-density lipoprotein (LDL), hepatitis C virus, Gram-positive and Gram-negative bacteria, and inorganic silica particles. However, the mechanisms by which SR-B1 recognizes diverse ligands remain unclear. We previously reported that a basic amino acid cluster consisting of K151, K156, and K395 at the extracellular apex of SR-B1 is essential for charge-dependent binding to silica and is distinct from the known HDL-binding site. In this study, homology modeling of SR-B1 revealed the HDL-binding site is oriented toward the basic cluster. Site-directed mutagenesis demonstrated that this basic cluster is required for HDL and, to a lesser extent, LDL binding, which in turn promotes binding to silica nanoparticles. The selective binding of SR-B1 to silica nanoparticles, but not to TiO<sub>2</sub> nanoparticles, latex nanoparticles, monosodium urate crystals, or multiwalled carbon nanotubes, depends on specific HDL- or LDL-silica interactions. These findings suggest that HDL, and potentially LDL, may underlie SR-B1's function as a muti-ligand membrane receptor.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"111235"},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146131942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.jbc.2026.111241
Yanyun Huang, Zhentao Zi, Chenliang Xia, Yi Rao
Bile acids (BAs), long known for roles in food emulsion, also function as biological signals. By measuring intracellular calcium, we have recently discovered that GPR39, a G protein-coupled receptor, is a receptor for 3-O-sulfated BAs including lithocholic acid 3-sulfate (LCAS), taurolithocholic acid 3-sulfate (TLCAS) and glycolithocholic acid 3-sulfate (GLCAS) in cultured cells and in pancreatic acinar cells. We have now used multiple assays from electrophysiologic recording in Xenopus oocytes, Ca2+ imaging, NanoBiT, ONE-GO, to TANGO to validate GPR39 activation by BAs. Among 30 BAs, only sulfated forms (LCAS, TLCAS and GLCAS) evoked GPR39 activation, activating 9 distinct Gα protein subtypes across the Gαq, Gαi, and Gα12/13 subfamilies. LCAS induced phosphorylation of ERK1/2 in the pancreas and the liver, which was markedly attenuated in Gpr39 knockout mice. Mutagenesis analysis identified the key residues essential for GPR39 signaling. Our results have revealed new signaling molecules downstream of GPR39 activation.
胆汁酸(BAs)在食品乳剂中的作用早已为人所知,它还具有生物信号的功能。通过测量细胞内钙,我们最近发现G蛋白偶联受体GPR39在培养细胞和胰腺腺泡细胞中是3- o -硫酸石胆酸3-硫酸盐(LCAS)、牛磺酸石胆酸3-硫酸盐(TLCAS)和糖colithocholic酸3-硫酸盐(GLCAS)的受体。我们现在使用多种检测方法,从爪蟾卵母细胞的电生理记录、Ca2+成像、NanoBiT、ONE-GO到TANGO,来验证BAs对GPR39的激活。在30种BAs中,只有硫酸酸化形式(LCAS、TLCAS和GLCAS)能激活GPR39,激活Gαq、Gαi和Gα12/13亚家族中的9种不同的Gα蛋白亚型。LCAS诱导胰腺和肝脏的ERK1/2磷酸化,Gpr39敲除小鼠的磷酸化明显减弱。诱变分析确定了GPR39信号传导所必需的关键残基。我们的研究结果揭示了GPR39激活下游的新信号分子。
{"title":"GPR39 mediated molecular signaling by bile acids.","authors":"Yanyun Huang, Zhentao Zi, Chenliang Xia, Yi Rao","doi":"10.1016/j.jbc.2026.111241","DOIUrl":"https://doi.org/10.1016/j.jbc.2026.111241","url":null,"abstract":"<p><p>Bile acids (BAs), long known for roles in food emulsion, also function as biological signals. By measuring intracellular calcium, we have recently discovered that GPR39, a G protein-coupled receptor, is a receptor for 3-O-sulfated BAs including lithocholic acid 3-sulfate (LCAS), taurolithocholic acid 3-sulfate (TLCAS) and glycolithocholic acid 3-sulfate (GLCAS) in cultured cells and in pancreatic acinar cells. We have now used multiple assays from electrophysiologic recording in Xenopus oocytes, Ca<sup>2+</sup> imaging, NanoBiT, ONE-GO, to TANGO to validate GPR39 activation by BAs. Among 30 BAs, only sulfated forms (LCAS, TLCAS and GLCAS) evoked GPR39 activation, activating 9 distinct Gα protein subtypes across the Gα<sub>q</sub>, Gα<sub>i</sub>, and Gα<sub>12/13</sub> subfamilies. LCAS induced phosphorylation of ERK1/2 in the pancreas and the liver, which was markedly attenuated in Gpr39 knockout mice. Mutagenesis analysis identified the key residues essential for GPR39 signaling. Our results have revealed new signaling molecules downstream of GPR39 activation.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"111241"},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146131910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.jbc.2026.111238
Nicholas D Urban, Kunal Gharat, Zachary J Mattiola, Ashley Scheutzow, Adam Klaiss, Sarah Tabler, Asa W Huffaker, Monique Grootveld, Mary E Skinner, Weiyang Zheng, Matthew J O'Meara, Janine Kirstein, Matthias C Truttmann
Targeted regulation of 70 kilodalton Heat Shock Protein (HSP70) chaperones, particularly the essential cognate heat shock protein (HSC70) and its Caenorhabditis elegans ortholog (HSP-1), may hold the key to improving cellular proteostasis and ameliorating aging-associated conditions linked to protein misfolding and aggregation. However, tools to selectively alter HSP70 chaperone activity remain elusive. In this study, we pioneer the development of two novel nanobodies, B12 and H5, which specifically bind to both recombinant and endogenous HSP-1. We show that these nanobodies, differing by only two amino acids in their complementarity-determining regions, bind specifically to HSP-1 and effectively reduce both HSP-1 ATPase activity and protein folding capacity in a dose-dependent manner in vitro. We further demonstrate in vivo expression of B12, but not H5, in transgenic C. elegans strains reduces heat-stress survival and proteotoxic-stress resistance, mirroring the effects of hsp-1 knockdown via RNA interference. Our findings suggest that these nanobodies can serve as effective and specific tools for inhibiting HSP-1 chaperone activity in vivo. These discoveries provide a foundation for future research exploring the therapeutic potential of HSP70-targeting nanobodies in aging and protein misfolding diseases.
{"title":"HSP-1-Specific Nanobodies Alter Chaperone Function in vitro and in vivo.","authors":"Nicholas D Urban, Kunal Gharat, Zachary J Mattiola, Ashley Scheutzow, Adam Klaiss, Sarah Tabler, Asa W Huffaker, Monique Grootveld, Mary E Skinner, Weiyang Zheng, Matthew J O'Meara, Janine Kirstein, Matthias C Truttmann","doi":"10.1016/j.jbc.2026.111238","DOIUrl":"10.1016/j.jbc.2026.111238","url":null,"abstract":"<p><p>Targeted regulation of 70 kilodalton Heat Shock Protein (HSP70) chaperones, particularly the essential cognate heat shock protein (HSC70) and its Caenorhabditis elegans ortholog (HSP-1), may hold the key to improving cellular proteostasis and ameliorating aging-associated conditions linked to protein misfolding and aggregation. However, tools to selectively alter HSP70 chaperone activity remain elusive. In this study, we pioneer the development of two novel nanobodies, B12 and H5, which specifically bind to both recombinant and endogenous HSP-1. We show that these nanobodies, differing by only two amino acids in their complementarity-determining regions, bind specifically to HSP-1 and effectively reduce both HSP-1 ATPase activity and protein folding capacity in a dose-dependent manner in vitro. We further demonstrate in vivo expression of B12, but not H5, in transgenic C. elegans strains reduces heat-stress survival and proteotoxic-stress resistance, mirroring the effects of hsp-1 knockdown via RNA interference. Our findings suggest that these nanobodies can serve as effective and specific tools for inhibiting HSP-1 chaperone activity in vivo. These discoveries provide a foundation for future research exploring the therapeutic potential of HSP70-targeting nanobodies in aging and protein misfolding diseases.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"111238"},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146131952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}