Obesity per se is rapidly emerging all over the planet and further accounts for many other life-threatening conditions, such as diabetes, cardiovascular diseases, and cancers. Decreased oxygen supply or increased relative oxygen consumption in the adipose tissue results in adipose tissue hypoxia, which is a hallmark of obesity. This review aims to provide an up-to-date overview of the hypoxia signaling in the adipose tissue. First, we summarize literature evidence to demonstrate that hypoxia is regularly observed during adipose tissue remodeling in human and rodent models of obesity. Next, we discuss how hypoxia-inducible factors (HIFs) are regulated and how adipose tissues behave in response to hypoxia. Then, the differential roles of adipose HIF-1α and HIF-2α in adipose tissue biology and obesity pathology are highlighted. Finally, the review emphasizes the importance of modulating adipose hypoxia as a therapeutic avenue to assist adipose tissues in functionally adapting to hypoxic conditions, ultimately promoting adipose health and improving outcomes due to obesity.
{"title":"Hypoxia signaling in the adipose tissue.","authors":"Phu M Huynh, Fenfen Wang, Yu A An","doi":"10.1093/jmcb/mjae039","DOIUrl":"https://doi.org/10.1093/jmcb/mjae039","url":null,"abstract":"<p><p>Obesity per se is rapidly emerging all over the planet and further accounts for many other life-threatening conditions, such as diabetes, cardiovascular diseases, and cancers. Decreased oxygen supply or increased relative oxygen consumption in the adipose tissue results in adipose tissue hypoxia, which is a hallmark of obesity. This review aims to provide an up-to-date overview of the hypoxia signaling in the adipose tissue. First, we summarize literature evidence to demonstrate that hypoxia is regularly observed during adipose tissue remodeling in human and rodent models of obesity. Next, we discuss how hypoxia-inducible factors (HIFs) are regulated and how adipose tissues behave in response to hypoxia. Then, the differential roles of adipose HIF-1α and HIF-2α in adipose tissue biology and obesity pathology are highlighted. Finally, the review emphasizes the importance of modulating adipose hypoxia as a therapeutic avenue to assist adipose tissues in functionally adapting to hypoxic conditions, ultimately promoting adipose health and improving outcomes due to obesity.</p>","PeriodicalId":16433,"journal":{"name":"Journal of Molecular Cell Biology","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142372098","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}
Cyrine Bentaleb, Souad Adrouche, Jade Finkelstein, Christelle Devisme, Nathalie Callens, Claude Capron, Morgane Bomsel, Fernando Real
Despite an undetectable plasma viral load as a result of antiretroviral therapy, HIV-1-infected individuals with poor immune reconstitution harbor infectious HIV-1 within their platelets. Megakaryocytes, as platelet precursors, are the likely cellular origin of these HIV-1-containing platelets. To investigate the mechanisms that allow megakaryocytes to support HIV-1 infection, we established in vitro models of viral infection using hematopoietic stem cell-derived megakaryocytes and the megakaryocytic MEG-01 cell line. We observed HIV-1 DNA provirus integration into the megakaryocyte cell genome, self-limiting virus production, and HIV-1 protein and RNA compartmentalization, which are hallmarks of HIV-1 infection in myeloid cells. In addition, following HIV-1 infection of megakaryocyte precursors, the expression of interferon-induced transmembrane protein 3 (IFITM3), an antiviral factor constitutively expressed in megakaryocytes, was inhibited in terminally differentiated HIV-1-infected megakaryocytes. IFITM3 knockdown in MEG-01 cells prior to infection led to enhanced HIV-1 infection, indicating that IFITM3 acts as an HIV-1 restriction factor in megakaryocytes. Together, these findings indicate that megakaryocyte precursors are susceptible to HIV-1 infection, leading to terminally differentiated megakaryocytes harboring virus in a process regulated by IFITM3. Megakaryocytes may thus constitute a neglected HIV-1 reservoir that warrants further study in order to develop improved antiretroviral therapies and to facilitate HIV-1 eradication.
{"title":"HIV-1 inhibits IFITM3 expression to promote the infection of megakaryocytes.","authors":"Cyrine Bentaleb, Souad Adrouche, Jade Finkelstein, Christelle Devisme, Nathalie Callens, Claude Capron, Morgane Bomsel, Fernando Real","doi":"10.1093/jmcb/mjae042","DOIUrl":"https://doi.org/10.1093/jmcb/mjae042","url":null,"abstract":"<p><p>Despite an undetectable plasma viral load as a result of antiretroviral therapy, HIV-1-infected individuals with poor immune reconstitution harbor infectious HIV-1 within their platelets. Megakaryocytes, as platelet precursors, are the likely cellular origin of these HIV-1-containing platelets. To investigate the mechanisms that allow megakaryocytes to support HIV-1 infection, we established in vitro models of viral infection using hematopoietic stem cell-derived megakaryocytes and the megakaryocytic MEG-01 cell line. We observed HIV-1 DNA provirus integration into the megakaryocyte cell genome, self-limiting virus production, and HIV-1 protein and RNA compartmentalization, which are hallmarks of HIV-1 infection in myeloid cells. In addition, following HIV-1 infection of megakaryocyte precursors, the expression of interferon-induced transmembrane protein 3 (IFITM3), an antiviral factor constitutively expressed in megakaryocytes, was inhibited in terminally differentiated HIV-1-infected megakaryocytes. IFITM3 knockdown in MEG-01 cells prior to infection led to enhanced HIV-1 infection, indicating that IFITM3 acts as an HIV-1 restriction factor in megakaryocytes. Together, these findings indicate that megakaryocyte precursors are susceptible to HIV-1 infection, leading to terminally differentiated megakaryocytes harboring virus in a process regulated by IFITM3. Megakaryocytes may thus constitute a neglected HIV-1 reservoir that warrants further study in order to develop improved antiretroviral therapies and to facilitate HIV-1 eradication.</p>","PeriodicalId":16433,"journal":{"name":"Journal of Molecular Cell Biology","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142361586","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}
Yueling Zhu, Shiyan Lin, Lingshen Meng, Min Sun, Maili Liu, Jingyuan Li, Chun Tang, Zhou Gong
ATP has been recognized as a hydrotrope in the phase separation process of intrinsically disordered proteins (IDPs). Surprisingly, when using the disordered RG/RGG-rich motif from HNRNPG protein as a model system, we discover a biphasic relationship between the ATP concentration and IDP phase separation. We show that at a relatively low ATP concentration, ATP dynamically interacts with the IDP, which neutralizes protein surface charges, promotes intermolecular interactions, and consequently promotes phase separation. We further demonstrate that ATP induces a compact conformation of the IDP, accounting for the reduced solvent exchange rate and lower compression ratio during phase separation. As ATP concentration increases, its hydrotropic properties emerge, leading to the dissolution of the phase-separated droplets. Our finding uncovers a complex mechanism by which ATP molecules modulate the structure, interaction, and phase separation of IDPs, and accounts for the distinct phase separation behaviors for the charge-rich RGG motif and other low-complexity IDPs.
ATP 被认为是本征无序蛋白(IDPs)相分离过程中的一种催化剂。令人惊奇的是,当使用 HNRNPG 蛋白中富含 RG/RGG 的无序结构作为模型系统时,我们发现 ATP 浓度与 IDP 相分离之间存在双相关系。我们发现,在 ATP 浓度相对较低时,ATP 会与 IDP 发生动态相互作用,从而中和蛋白质表面电荷,促进分子间相互作用,进而促进相分离。我们进一步证明,ATP 会诱导 IDP 形成紧凑的构象,这也是相分离过程中溶剂交换率降低和压缩率降低的原因。随着 ATP 浓度的增加,它的趋水特性逐渐显现,从而导致相分离液滴的溶解。我们的发现揭示了 ATP 分子调节 IDP 的结构、相互作用和相分离的复杂机制,并解释了富电荷 RGG 主题和其他低复杂度 IDP 的不同相分离行为。
{"title":"ATP promotes protein coacervation through conformational compaction.","authors":"Yueling Zhu, Shiyan Lin, Lingshen Meng, Min Sun, Maili Liu, Jingyuan Li, Chun Tang, Zhou Gong","doi":"10.1093/jmcb/mjae038","DOIUrl":"https://doi.org/10.1093/jmcb/mjae038","url":null,"abstract":"<p><p>ATP has been recognized as a hydrotrope in the phase separation process of intrinsically disordered proteins (IDPs). Surprisingly, when using the disordered RG/RGG-rich motif from HNRNPG protein as a model system, we discover a biphasic relationship between the ATP concentration and IDP phase separation. We show that at a relatively low ATP concentration, ATP dynamically interacts with the IDP, which neutralizes protein surface charges, promotes intermolecular interactions, and consequently promotes phase separation. We further demonstrate that ATP induces a compact conformation of the IDP, accounting for the reduced solvent exchange rate and lower compression ratio during phase separation. As ATP concentration increases, its hydrotropic properties emerge, leading to the dissolution of the phase-separated droplets. Our finding uncovers a complex mechanism by which ATP molecules modulate the structure, interaction, and phase separation of IDPs, and accounts for the distinct phase separation behaviors for the charge-rich RGG motif and other low-complexity IDPs.</p>","PeriodicalId":16433,"journal":{"name":"Journal of Molecular Cell Biology","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142361585","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}
Yuhan Lou, Litao Wu, Wanlin Cai, Huan Deng, Rong Sang, Shanshan Xie, Xiao Xu, Xin Yuan, Cheng Wu, Man Xu, Wanzhong Ge, Yongmei Xi, Xiaohang Yang
Defects in the FAcilitates Chromatin Transcription (FACT) complex, a histone chaperone composed of SSRP1 and SUPT16H, are implicated in intellectual disability. Here, we reveal that the FACT complex promotes glycolysis and sustains the correct cell fate of neural stem cells/neuroblasts in the Drosophila 3rd instar larval central brain. We show that the FACT complex binds to the promoter region of the estrogen-related receptor (ERR) gene and positively regulates ERR expression. ERR is known to act as an aerobic glycolytic switch by upregulating the enzymes required for glycolysis. Dysfunction of the FACT complex leads to the downregulation of ERR transcription, resulting in a decreased ratio of glycolysis to oxidative phosphorylation (G/O) in neuroblasts. Consequently, neuroblasts exhibit smaller cell sizes, lower proliferation potential, and altered cell fates. Overexpression of ERR or suppression of mitochondrial oxidative phosphorylation in neuroblasts increases the relative G/O ratio and rescues defective phenotypes caused by dysfunction of the FACT complex. Thus, the G/O ratio, mediated by the FACT complex, plays a crucial role in neuroblast cell fate maintenance. Our study may shed light on the mechanism by which mutations in the FACT complex lead to intellectual disability in humans.
{"title":"The FAcilitates Chromatin Transcription complex regulates the ratio of glycolysis to oxidative phosphorylation in neural stem cells.","authors":"Yuhan Lou, Litao Wu, Wanlin Cai, Huan Deng, Rong Sang, Shanshan Xie, Xiao Xu, Xin Yuan, Cheng Wu, Man Xu, Wanzhong Ge, Yongmei Xi, Xiaohang Yang","doi":"10.1093/jmcb/mjae017","DOIUrl":"10.1093/jmcb/mjae017","url":null,"abstract":"<p><p>Defects in the FAcilitates Chromatin Transcription (FACT) complex, a histone chaperone composed of SSRP1 and SUPT16H, are implicated in intellectual disability. Here, we reveal that the FACT complex promotes glycolysis and sustains the correct cell fate of neural stem cells/neuroblasts in the Drosophila 3rd instar larval central brain. We show that the FACT complex binds to the promoter region of the estrogen-related receptor (ERR) gene and positively regulates ERR expression. ERR is known to act as an aerobic glycolytic switch by upregulating the enzymes required for glycolysis. Dysfunction of the FACT complex leads to the downregulation of ERR transcription, resulting in a decreased ratio of glycolysis to oxidative phosphorylation (G/O) in neuroblasts. Consequently, neuroblasts exhibit smaller cell sizes, lower proliferation potential, and altered cell fates. Overexpression of ERR or suppression of mitochondrial oxidative phosphorylation in neuroblasts increases the relative G/O ratio and rescues defective phenotypes caused by dysfunction of the FACT complex. Thus, the G/O ratio, mediated by the FACT complex, plays a crucial role in neuroblast cell fate maintenance. Our study may shed light on the mechanism by which mutations in the FACT complex lead to intellectual disability in humans.</p>","PeriodicalId":16433,"journal":{"name":"Journal of Molecular Cell Biology","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11467811/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140891908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fusion pore opening is a transient intermediate state of synaptic vesicle exocytosis, which is highly dynamic and precisely regulated by the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex and synaptotagmin-1 (Syt1). Yet, the regulatory mechanism is not fully understood. In this work, using single-channel membrane fusion electrophysiology, we determined that SNAREpins are important for driving fusion pore opening and dilation but incapable of regulating the dynamics. When Syt1 was added, the closing frequency of fusion pores significantly increased, while the radius of fusion pores mildly decreased. In response to Ca2+, SNARE/Syt1 greatly increased the radius of fusion pores and reduced their closing frequency. Moreover, the residue F349 in the C2B domain of Syt1, which mediates Syt1 oligomerization, was required for clamping fusion pore opening in the absence of Ca2+, probably by extending the distance between the two membranes. Finally, in Ca2+-triggered fusion, the primary interface between SNARE and Syt1 plays a critical role in stabilizing and dilating the fusion pore, while the polybasic region of Syt1 C2B domain has a mild effect on increasing the radius of the fusion pore. In summary, our results suggest that Syt1, SNARE, and the anionic membrane synergically orchestrate the dynamics of fusion pore opening in synaptic vesicle exocytosis.
{"title":"Synergistic regulation of fusion pore opening and dilation by SNARE and synaptotagmin-1.","authors":"Kaiju Li, Kaiyu Li, Jiaqi Fan, Xing Zhang, Chengyan Tao, Yijuan Xiang, Lele Cui, Hao Li, Minghan Li, Yanjing Zhang, Jia Geng, Ying Lai","doi":"10.1093/jmcb/mjae011","DOIUrl":"10.1093/jmcb/mjae011","url":null,"abstract":"<p><p>Fusion pore opening is a transient intermediate state of synaptic vesicle exocytosis, which is highly dynamic and precisely regulated by the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex and synaptotagmin-1 (Syt1). Yet, the regulatory mechanism is not fully understood. In this work, using single-channel membrane fusion electrophysiology, we determined that SNAREpins are important for driving fusion pore opening and dilation but incapable of regulating the dynamics. When Syt1 was added, the closing frequency of fusion pores significantly increased, while the radius of fusion pores mildly decreased. In response to Ca2+, SNARE/Syt1 greatly increased the radius of fusion pores and reduced their closing frequency. Moreover, the residue F349 in the C2B domain of Syt1, which mediates Syt1 oligomerization, was required for clamping fusion pore opening in the absence of Ca2+, probably by extending the distance between the two membranes. Finally, in Ca2+-triggered fusion, the primary interface between SNARE and Syt1 plays a critical role in stabilizing and dilating the fusion pore, while the polybasic region of Syt1 C2B domain has a mild effect on increasing the radius of the fusion pore. In summary, our results suggest that Syt1, SNARE, and the anionic membrane synergically orchestrate the dynamics of fusion pore opening in synaptic vesicle exocytosis.</p>","PeriodicalId":16433,"journal":{"name":"Journal of Molecular Cell Biology","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11472156/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140039644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Umer Ejaz, Zhen Dou, Phil Y Yao, Zhikai Wang, Xing Liu, Xuebiao Yao
Chromothripsis, a type of complex chromosomal rearrangement originally known as chromoanagenesis, has been a subject of extensive investigation due to its potential role in various diseases, particularly cancer. Chromothripsis involves the rapid acquisition of tens to hundreds of structural rearrangements within a short period, leading to complex alterations in one or a few chromosomes. This phenomenon is triggered by chromosome mis-segregation during mitosis. Errors in accurate chromosome segregation lead to formation of aberrant structural entities such as micronuclei or chromatin bridges. The association between chromothripsis and cancer has attracted significant interest, with potential implications for tumorigenesis and disease prognosis. This review aims to explore the intricate mechanisms and consequences of chromothripsis, with a specific focus on its association with mitotic perturbations. Herein, we discuss a comprehensive analysis of crucial molecular entities and pathways, exploring the intricate roles of the CIP2A-TOPBP1 complex, micronuclei formation, chromatin bridge processing, DNA damage repair, and mitotic checkpoints. Moreover, the review will highlight recent advancements in identifying potential therapeutic targets and the underlying molecular mechanisms associated with chromothripsis, paving the way for future therapeutic interventions in various diseases.
{"title":"Chromothripsis: an emerging crossroad from aberrant mitosis to therapeutic opportunities.","authors":"Umer Ejaz, Zhen Dou, Phil Y Yao, Zhikai Wang, Xing Liu, Xuebiao Yao","doi":"10.1093/jmcb/mjae016","DOIUrl":"10.1093/jmcb/mjae016","url":null,"abstract":"<p><p>Chromothripsis, a type of complex chromosomal rearrangement originally known as chromoanagenesis, has been a subject of extensive investigation due to its potential role in various diseases, particularly cancer. Chromothripsis involves the rapid acquisition of tens to hundreds of structural rearrangements within a short period, leading to complex alterations in one or a few chromosomes. This phenomenon is triggered by chromosome mis-segregation during mitosis. Errors in accurate chromosome segregation lead to formation of aberrant structural entities such as micronuclei or chromatin bridges. The association between chromothripsis and cancer has attracted significant interest, with potential implications for tumorigenesis and disease prognosis. This review aims to explore the intricate mechanisms and consequences of chromothripsis, with a specific focus on its association with mitotic perturbations. Herein, we discuss a comprehensive analysis of crucial molecular entities and pathways, exploring the intricate roles of the CIP2A-TOPBP1 complex, micronuclei formation, chromatin bridge processing, DNA damage repair, and mitotic checkpoints. Moreover, the review will highlight recent advancements in identifying potential therapeutic targets and the underlying molecular mechanisms associated with chromothripsis, paving the way for future therapeutic interventions in various diseases.</p>","PeriodicalId":16433,"journal":{"name":"Journal of Molecular Cell Biology","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11487160/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140863118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ziyan Xu, Yongrui Liu, Fudong Li, Yi Yang, Hong Zhang, Xing Liu, Xin Xie, Xianjun Chen, Yunyu Shi, Liang Zhang
Telomeres are repetitive DNA sequences and associated protein complexes located at the end of chromatin. As a result of the DNA replication ending issue, telomeric DNA shortens during each cell cycle. The shelterin protein complex caps telomeric ends and forms a high-order protein-DNA structure to protect telomeric DNA. The stability of telomeres is critical for cellular function and is related to the progression of many human diseases. Telomeric repeat-containing RNA (TERRA) is a noncoding RNA transcribed from telomeric DNA regions. TERRA plays an essential role in regulating and maintaining the stability of telomeres. Heterogeneous nuclear ribonucleoproteins (hnRNPs) are RNA-binding proteins associated with complex and diverse biological processes. HnRNPA1 can recognize both TERRA and telomeric DNA. Previous research reported that hnRNPA1, TERRA, and POT1, a component of the shelterin complex, worked coordinately and displaced replication protein A from telomeric ssDNA after DNA replication, promoting telomere capping to preserve genomic integrity. However, the detailed molecular mechanism has remained unclear for over twenty years. Our study revealed the molecular structure through which the hnRNPA1 UP1 domain interacts with TERRA. Through structural analysis, we identified critical residues on the interacting surface between UP1 and TERRA. Furthermore, we proved that nucleic acids significantly increase the phase separation ability of hnRNPA1 and disrupting the UP1-TERRA interaction extraordinarily affects hnRNPA1 droplet formation both in vitro and in vivo. Taken together, these data revealed the molecular mechanism of the droplet formation of hnRNPA1 and TERRA and the possible function of the droplets for maintaining genomic stability.
端粒是位于染色质末端的重复 DNA 序列和相关蛋白质复合物。由于DNA复制结束的问题,端粒DNA在每个细胞周期中都会缩短。庇护蛋白复合物覆盖端粒末端,形成高阶蛋白-DNA 结构,保护端粒 DNA。端粒的稳定性对细胞功能至关重要,并与许多人类疾病的进展有关。含端粒重复序列的RNA(TERRA)是一种从端粒DNA区域转录的非编码RNA。TERRA 在调节和维持端粒稳定性方面发挥着重要作用。异质核核糖核蛋白(hnRNPs)是与复杂多样的生物过程相关的 RNA 结合蛋白。HnRNPA1 可识别 TERRA 和端粒 DNA。以前的研究报告称,hnRNPA1、TERRA 和庇护蛋白复合物的一个成分 POT1 协同工作,在 DNA 复制后将复制蛋白 A 从端粒 ssDNA 中移除,促进端粒封顶以保持基因组完整性。然而,详细的分子机制二十多年来一直不清楚。我们的研究揭示了 hnRNPA1 UP1 结构域与 TERRA 相互作用的分子结构。通过结构分析,我们确定了 UP1 与 TERRA 相互作用表面上的关键残基。此外,我们还证明了核酸能显著提高 hnRNPA1 的相分离能力,而破坏 UP1 与 TERRA 的相互作用会极大地影响 hnRNPA1 在体外和体内的液滴形成。综上所述,这些数据揭示了 hnRNPA1 和 TERRA 形成液滴的分子机制以及液滴在维持基因组稳定性方面的可能功能。
{"title":"Phase separation of hnRNPA1 and TERRA regulates telomeric stability.","authors":"Ziyan Xu, Yongrui Liu, Fudong Li, Yi Yang, Hong Zhang, Xing Liu, Xin Xie, Xianjun Chen, Yunyu Shi, Liang Zhang","doi":"10.1093/jmcb/mjae037","DOIUrl":"https://doi.org/10.1093/jmcb/mjae037","url":null,"abstract":"<p><p>Telomeres are repetitive DNA sequences and associated protein complexes located at the end of chromatin. As a result of the DNA replication ending issue, telomeric DNA shortens during each cell cycle. The shelterin protein complex caps telomeric ends and forms a high-order protein-DNA structure to protect telomeric DNA. The stability of telomeres is critical for cellular function and is related to the progression of many human diseases. Telomeric repeat-containing RNA (TERRA) is a noncoding RNA transcribed from telomeric DNA regions. TERRA plays an essential role in regulating and maintaining the stability of telomeres. Heterogeneous nuclear ribonucleoproteins (hnRNPs) are RNA-binding proteins associated with complex and diverse biological processes. HnRNPA1 can recognize both TERRA and telomeric DNA. Previous research reported that hnRNPA1, TERRA, and POT1, a component of the shelterin complex, worked coordinately and displaced replication protein A from telomeric ssDNA after DNA replication, promoting telomere capping to preserve genomic integrity. However, the detailed molecular mechanism has remained unclear for over twenty years. Our study revealed the molecular structure through which the hnRNPA1 UP1 domain interacts with TERRA. Through structural analysis, we identified critical residues on the interacting surface between UP1 and TERRA. Furthermore, we proved that nucleic acids significantly increase the phase separation ability of hnRNPA1 and disrupting the UP1-TERRA interaction extraordinarily affects hnRNPA1 droplet formation both in vitro and in vivo. Taken together, these data revealed the molecular mechanism of the droplet formation of hnRNPA1 and TERRA and the possible function of the droplets for maintaining genomic stability.</p>","PeriodicalId":16433,"journal":{"name":"Journal of Molecular Cell Biology","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307933","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}
Rui-Lin Tian, Tian-Xiang Wang, Zi-Xuan Huang, Zhen Yang, Kun-Liang Guan, Yue Xiong, Pu Wang, Dan Ye
Ferroptosis is a non-apoptotic mode of cell death characterized by iron-dependent accumulation of lipid peroxidation. While lipid radical elimination reaction catalyzed by glutathione peroxidase 4 (GPX4) is a major anti-ferroptosis mechanism, inhibiting this pathway pharmaceutically shows promise as an anti-tumor strategy. However, certain tumor cells exhibit redundancy in lipid radical elimination pathways, rendering them unresponsive to GPX4 inhibitors. In this study, we conducted screens across different cancer cell lines and FDA-approved drugs, leading to the identification of temsirolimus in combination with the GPX4 inhibitor RSL3 as a potent inducer of ferroptosis in liver cancer cells. Mechanistically, temsirolimus sensitized liver cancer cells to ferroptosis by directly binding to and inhibiting ferroptosis suppressor protein 1 (FSP1) enzyme. Notably, while temsirolimus is recognized as a potent mTOR inhibitor, its ferroptosis-inducing effect is primarily attributed to its inhibition of FSP1 rather than mTOR activity. By performing in vitro colony formation assays and in vivo tumor xenograft models, we demonstrated that the combination of temsirolimus and RSL3 effectively suppressed liver tumor progression. This tumoricidal effect was associated with increased lipid peroxidation and induction of ferroptosis. In conclusion, our findings underscore the potential of combining multi-target ferroptosis-inducing agents to circumvent resistance to ferroptosis in liver cancer cells and highlight temsirolimus as a promising FSP1 inhibitor and ferroptosis inducer, which also deserves further investigation in translational medicine.
{"title":"Temsirolimus inhibits FSP1 enzyme activity to induce ferroptosis and restrain liver cancer progression.","authors":"Rui-Lin Tian, Tian-Xiang Wang, Zi-Xuan Huang, Zhen Yang, Kun-Liang Guan, Yue Xiong, Pu Wang, Dan Ye","doi":"10.1093/jmcb/mjae036","DOIUrl":"https://doi.org/10.1093/jmcb/mjae036","url":null,"abstract":"<p><p>Ferroptosis is a non-apoptotic mode of cell death characterized by iron-dependent accumulation of lipid peroxidation. While lipid radical elimination reaction catalyzed by glutathione peroxidase 4 (GPX4) is a major anti-ferroptosis mechanism, inhibiting this pathway pharmaceutically shows promise as an anti-tumor strategy. However, certain tumor cells exhibit redundancy in lipid radical elimination pathways, rendering them unresponsive to GPX4 inhibitors. In this study, we conducted screens across different cancer cell lines and FDA-approved drugs, leading to the identification of temsirolimus in combination with the GPX4 inhibitor RSL3 as a potent inducer of ferroptosis in liver cancer cells. Mechanistically, temsirolimus sensitized liver cancer cells to ferroptosis by directly binding to and inhibiting ferroptosis suppressor protein 1 (FSP1) enzyme. Notably, while temsirolimus is recognized as a potent mTOR inhibitor, its ferroptosis-inducing effect is primarily attributed to its inhibition of FSP1 rather than mTOR activity. By performing in vitro colony formation assays and in vivo tumor xenograft models, we demonstrated that the combination of temsirolimus and RSL3 effectively suppressed liver tumor progression. This tumoricidal effect was associated with increased lipid peroxidation and induction of ferroptosis. In conclusion, our findings underscore the potential of combining multi-target ferroptosis-inducing agents to circumvent resistance to ferroptosis in liver cancer cells and highlight temsirolimus as a promising FSP1 inhibitor and ferroptosis inducer, which also deserves further investigation in translational medicine.</p>","PeriodicalId":16433,"journal":{"name":"Journal of Molecular Cell Biology","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307934","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}
{"title":"Unleashing the power of antigen-presenting neutrophils.","authors":"Yingcheng Wu, Jiaqiang Ma, Qiang Gao","doi":"10.1093/jmcb/mjae034","DOIUrl":"https://doi.org/10.1093/jmcb/mjae034","url":null,"abstract":"","PeriodicalId":16433,"journal":{"name":"Journal of Molecular Cell Biology","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142289440","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}