Pub Date : 2024-10-07Epub Date: 2024-06-18DOI: 10.1083/jcb.202310067
Alexia Caillier, David Oleksyn, Deborah J Fowell, Jim Miller, Patrick W Oakes
Immune cells are highly dynamic and able to migrate through environments with diverse biochemical and mechanical compositions. Their migration has classically been defined as amoeboid under the assumption that it is integrin independent. Here, we show that activated primary Th1 T cells require both confinement and extracellular matrix proteins to migrate efficiently. This migration is mediated through small and dynamic focal adhesions that are composed of the same proteins associated with canonical mesenchymal cell focal adhesions, such as integrins, talin, and vinculin. These focal adhesions, furthermore, localize to sites of contractile traction stresses, enabling T cells to pull themselves through confined spaces. Finally, we show that Th1 T cells preferentially follow tracks of other T cells, suggesting that these adhesions modify the extracellular matrix to provide additional environmental guidance cues. These results demonstrate not only that the boundaries between amoeboid and mesenchymal migration modes are ambiguous, but that integrin-mediated focal adhesions play a key role in T cell motility.
免疫细胞具有高度动态性,能够在具有不同生化和机械成分的环境中迁移。根据独立于整合素的假设,它们的迁移通常被定义为非膜性迁移。在这里,我们发现活化的原发性 Th1 T 细胞需要封闭和细胞外基质蛋白才能有效迁移。这种迁移是通过小而动态的局灶粘附介导的,局灶粘附由与典型间充质细胞局灶粘附相关的相同蛋白组成,如整合素、塔林和长链蛋白。此外,这些局灶粘附还定位在收缩牵引应力的部位,使 T 细胞能将自己拉过狭窄的空间。最后,我们发现 Th1 T 细胞会优先追随其他 T 细胞的轨迹,这表明这些粘附改变了细胞外基质,从而提供了额外的环境引导线索。这些结果不仅证明了非变形和间质迁移模式之间的界限模糊不清,而且证明了整合素介导的局灶粘附在 T 细胞运动中起着关键作用。
{"title":"T cells use focal adhesions to pull themselves through confined environments.","authors":"Alexia Caillier, David Oleksyn, Deborah J Fowell, Jim Miller, Patrick W Oakes","doi":"10.1083/jcb.202310067","DOIUrl":"10.1083/jcb.202310067","url":null,"abstract":"<p><p>Immune cells are highly dynamic and able to migrate through environments with diverse biochemical and mechanical compositions. Their migration has classically been defined as amoeboid under the assumption that it is integrin independent. Here, we show that activated primary Th1 T cells require both confinement and extracellular matrix proteins to migrate efficiently. This migration is mediated through small and dynamic focal adhesions that are composed of the same proteins associated with canonical mesenchymal cell focal adhesions, such as integrins, talin, and vinculin. These focal adhesions, furthermore, localize to sites of contractile traction stresses, enabling T cells to pull themselves through confined spaces. Finally, we show that Th1 T cells preferentially follow tracks of other T cells, suggesting that these adhesions modify the extracellular matrix to provide additional environmental guidance cues. These results demonstrate not only that the boundaries between amoeboid and mesenchymal migration modes are ambiguous, but that integrin-mediated focal adhesions play a key role in T cell motility.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 10","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11187980/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141419273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07Epub Date: 2024-07-03DOI: 10.1083/jcb.202305093
Wendy M McKimpson, Sophia Spiegel, Maria Mukhanova, Michael Kraakman, Wen Du, Takumi Kitamoto, Junjie Yu, Zhaobin Deng, Utpal Pajvani, Domenico Accili
Calorie restriction increases lifespan. Among the tissue-specific protective effects of calorie restriction, the impact on the gastrointestinal tract remains unclear. We report increased numbers of chromogranin A-positive (+), including orexigenic ghrelin+ cells, in the stomach of calorie-restricted mice. This effect was accompanied by increased Notch target Hes1 and Notch ligand Jag1 and was reversed by blocking Notch with DAPT, a gamma-secretase inhibitor. Primary cultures and genetically modified reporter mice show that increased endocrine cell abundance is due to altered Lgr5+ stem and Neurog3+ endocrine progenitor cell proliferation. Different from the intestine, calorie restriction decreased gastric Lgr5+ stem cells, while increasing a FOXO1/Neurog3+ subpopulation of endocrine progenitors in a Notch-dependent manner. Further, activation of FOXO1 was sufficient to promote endocrine cell differentiation independent of Notch. The Notch inhibitor PF-03084014 or ghrelin receptor antagonist GHRP-6 reversed the phenotypic effects of calorie restriction in mice. Tirzepatide additionally expanded ghrelin+ cells in mice. In summary, calorie restriction promotes Notch-dependent, FOXO1-regulated gastric endocrine cell differentiation.
限制卡路里摄入会延长寿命。在卡路里限制对特定组织的保护作用中,对胃肠道的影响仍不清楚。我们报告了限制卡路里摄入的小鼠胃中嗜铬粒蛋白 A 阳性(+)细胞数量的增加,其中包括嗜食性胃泌素+细胞。这种效应伴随着Notch靶标Hes1和Notch配体Jag1的增加,并通过使用γ-分泌酶抑制剂DAPT阻断Notch而逆转。原代培养物和转基因报告小鼠表明,内分泌细胞数量的增加是由于Lgr5+干细胞和Neurog3+内分泌祖细胞增殖的改变。与肠道不同的是,卡路里限制减少了胃Lgr5+干细胞,而内分泌祖细胞的FOXO1/Neurog3+亚群则以Notch依赖性方式增加。此外,FOXO1的激活足以促进独立于Notch的内分泌细胞分化。Notch抑制剂PF-03084014或胃泌素受体拮抗剂GHRP-6可逆转小鼠热量限制的表型效应。替扎帕肽还能扩大小鼠的胃泌素+细胞。总之,卡路里限制促进了Notch依赖性、FOXO1调控的胃内分泌细胞分化。
{"title":"Calorie restriction activates a gastric Notch-FOXO1 pathway to expand ghrelin cells.","authors":"Wendy M McKimpson, Sophia Spiegel, Maria Mukhanova, Michael Kraakman, Wen Du, Takumi Kitamoto, Junjie Yu, Zhaobin Deng, Utpal Pajvani, Domenico Accili","doi":"10.1083/jcb.202305093","DOIUrl":"10.1083/jcb.202305093","url":null,"abstract":"<p><p>Calorie restriction increases lifespan. Among the tissue-specific protective effects of calorie restriction, the impact on the gastrointestinal tract remains unclear. We report increased numbers of chromogranin A-positive (+), including orexigenic ghrelin+ cells, in the stomach of calorie-restricted mice. This effect was accompanied by increased Notch target Hes1 and Notch ligand Jag1 and was reversed by blocking Notch with DAPT, a gamma-secretase inhibitor. Primary cultures and genetically modified reporter mice show that increased endocrine cell abundance is due to altered Lgr5+ stem and Neurog3+ endocrine progenitor cell proliferation. Different from the intestine, calorie restriction decreased gastric Lgr5+ stem cells, while increasing a FOXO1/Neurog3+ subpopulation of endocrine progenitors in a Notch-dependent manner. Further, activation of FOXO1 was sufficient to promote endocrine cell differentiation independent of Notch. The Notch inhibitor PF-03084014 or ghrelin receptor antagonist GHRP-6 reversed the phenotypic effects of calorie restriction in mice. Tirzepatide additionally expanded ghrelin+ cells in mice. In summary, calorie restriction promotes Notch-dependent, FOXO1-regulated gastric endocrine cell differentiation.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 10","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11222742/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141492064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07Epub Date: 2024-07-15DOI: 10.1083/jcb.202307146
Claire L Riggs, Nancy Kedersha, Misheel Amarsanaa, Safiyah Noor Zubair, Pavel Ivanov, Paul Anderson
Stress triggers the formation of two distinct cytoplasmic biomolecular condensates: stress granules (SGs) and processing bodies (PBs), both of which may contribute to stress-responsive translation regulation. Though PBs can be present constitutively, stress can increase their number and size and lead to their interaction with stress-induced SGs. The mechanism of such interaction, however, is largely unknown. Formation of canonical SGs requires the RNA binding protein Ubiquitin-Associated Protein 2-Like (UBAP2L), which is a central SG node protein in the RNA-protein interaction network of SGs and PBs. UBAP2L binds to the essential SG and PB proteins G3BP and DDX6, respectively. Research on UBAP2L has mostly focused on its role in SGs, but not its connection to PBs. We find that UBAP2L is not solely an SG protein but also localizes to PBs in certain conditions, contributes to PB biogenesis and SG-PB interactions, and can nucleate hybrid granules containing SG and PB components in cells. These findings inform a new model for SG and PB formation in the context of UBAP2L's role.
{"title":"UBAP2L contributes to formation of P-bodies and modulates their association with stress granules.","authors":"Claire L Riggs, Nancy Kedersha, Misheel Amarsanaa, Safiyah Noor Zubair, Pavel Ivanov, Paul Anderson","doi":"10.1083/jcb.202307146","DOIUrl":"10.1083/jcb.202307146","url":null,"abstract":"<p><p>Stress triggers the formation of two distinct cytoplasmic biomolecular condensates: stress granules (SGs) and processing bodies (PBs), both of which may contribute to stress-responsive translation regulation. Though PBs can be present constitutively, stress can increase their number and size and lead to their interaction with stress-induced SGs. The mechanism of such interaction, however, is largely unknown. Formation of canonical SGs requires the RNA binding protein Ubiquitin-Associated Protein 2-Like (UBAP2L), which is a central SG node protein in the RNA-protein interaction network of SGs and PBs. UBAP2L binds to the essential SG and PB proteins G3BP and DDX6, respectively. Research on UBAP2L has mostly focused on its role in SGs, but not its connection to PBs. We find that UBAP2L is not solely an SG protein but also localizes to PBs in certain conditions, contributes to PB biogenesis and SG-PB interactions, and can nucleate hybrid granules containing SG and PB components in cells. These findings inform a new model for SG and PB formation in the context of UBAP2L's role.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 10","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11248227/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141616524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07Epub Date: 2024-08-12DOI: 10.1083/jcb.202304031
Shue Chen, Yang Sun, Yuling Qin, Lan Yang, Zhenhua Hao, Zhihao Xu, Mikael Björklund, Wei Liu, Zhi Hong
Mitochondrial functions can be regulated by membrane contact sites with the endoplasmic reticulum (ER). These mitochondria-ER contact sites (MERCs) are functionally heterogeneous and maintained by various tethers. Here, we found that REEP5, an ER tubule-shaping protein, interacts with Mitofusins 1/2 to mediate mitochondrial distribution throughout the cytosol by a new transport mechanism, mitochondrial "hitchhiking" with tubular ER on microtubules. REEP5 depletion led to reduced tethering and increased perinuclear localization of mitochondria. Conversely, increasing REEP5 expression facilitated mitochondrial distribution throughout the cytoplasm. Rapamycin-induced irreversible REEP5-MFN1/2 interaction led to mitochondrial hyperfusion, implying that the dynamic release of mitochondria from tethering is necessary for normal mitochondrial distribution and dynamics. Functionally, disruption of MFN2-REEP5 interaction dynamics by forced dimerization or silencing REEP5 modulated the production of mitochondrial reactive oxygen species (ROS). Overall, our results indicate that dynamic REEP5-MFN1/2 interaction mediates cytosolic distribution and connectivity of the mitochondrial network by "hitchhiking" and this process regulates mitochondrial ROS, which is vital for multiple physiological functions.
{"title":"Dynamic interaction of REEP5-MFN1/2 enables mitochondrial hitchhiking on tubular ER.","authors":"Shue Chen, Yang Sun, Yuling Qin, Lan Yang, Zhenhua Hao, Zhihao Xu, Mikael Björklund, Wei Liu, Zhi Hong","doi":"10.1083/jcb.202304031","DOIUrl":"10.1083/jcb.202304031","url":null,"abstract":"<p><p>Mitochondrial functions can be regulated by membrane contact sites with the endoplasmic reticulum (ER). These mitochondria-ER contact sites (MERCs) are functionally heterogeneous and maintained by various tethers. Here, we found that REEP5, an ER tubule-shaping protein, interacts with Mitofusins 1/2 to mediate mitochondrial distribution throughout the cytosol by a new transport mechanism, mitochondrial \"hitchhiking\" with tubular ER on microtubules. REEP5 depletion led to reduced tethering and increased perinuclear localization of mitochondria. Conversely, increasing REEP5 expression facilitated mitochondrial distribution throughout the cytoplasm. Rapamycin-induced irreversible REEP5-MFN1/2 interaction led to mitochondrial hyperfusion, implying that the dynamic release of mitochondria from tethering is necessary for normal mitochondrial distribution and dynamics. Functionally, disruption of MFN2-REEP5 interaction dynamics by forced dimerization or silencing REEP5 modulated the production of mitochondrial reactive oxygen species (ROS). Overall, our results indicate that dynamic REEP5-MFN1/2 interaction mediates cytosolic distribution and connectivity of the mitochondrial network by \"hitchhiking\" and this process regulates mitochondrial ROS, which is vital for multiple physiological functions.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 10","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11318672/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141916809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07Epub Date: 2024-07-01DOI: 10.1083/jcb.202310022
David Salvador-Garcia, Li Jin, Andrew Hensley, Mert Gölcük, Emmanuel Gallaud, Sami Chaaban, Fillip Port, Alessio Vagnoni, Vicente José Planelles-Herrero, Mark A McClintock, Emmanuel Derivery, Andrew P Carter, Régis Giet, Mert Gür, Ahmet Yildiz, Simon L Bullock
The diverse roles of the dynein motor in shaping microtubule networks and cargo transport complicate in vivo analysis of its functions significantly. To address this issue, we have generated a series of missense mutations in Drosophila Dynein heavy chain. We show that mutations associated with human neurological disease cause a range of defects, including impaired cargo trafficking in neurons. We also describe a novel microtubule-binding domain mutation that specifically blocks the metaphase-anaphase transition during mitosis in the embryo. This effect is independent from dynein's canonical role in silencing the spindle assembly checkpoint. Optical trapping of purified dynein complexes reveals that this mutation only compromises motor performance under load, a finding rationalized by the results of all-atom molecular dynamics simulations. We propose that dynein has a novel function in anaphase progression that depends on it operating in a specific load regime. More broadly, our work illustrates how in vivo functions of motors can be dissected by manipulating their mechanical properties.
{"title":"A force-sensitive mutation reveals a non-canonical role for dynein in anaphase progression.","authors":"David Salvador-Garcia, Li Jin, Andrew Hensley, Mert Gölcük, Emmanuel Gallaud, Sami Chaaban, Fillip Port, Alessio Vagnoni, Vicente José Planelles-Herrero, Mark A McClintock, Emmanuel Derivery, Andrew P Carter, Régis Giet, Mert Gür, Ahmet Yildiz, Simon L Bullock","doi":"10.1083/jcb.202310022","DOIUrl":"10.1083/jcb.202310022","url":null,"abstract":"<p><p>The diverse roles of the dynein motor in shaping microtubule networks and cargo transport complicate in vivo analysis of its functions significantly. To address this issue, we have generated a series of missense mutations in Drosophila Dynein heavy chain. We show that mutations associated with human neurological disease cause a range of defects, including impaired cargo trafficking in neurons. We also describe a novel microtubule-binding domain mutation that specifically blocks the metaphase-anaphase transition during mitosis in the embryo. This effect is independent from dynein's canonical role in silencing the spindle assembly checkpoint. Optical trapping of purified dynein complexes reveals that this mutation only compromises motor performance under load, a finding rationalized by the results of all-atom molecular dynamics simulations. We propose that dynein has a novel function in anaphase progression that depends on it operating in a specific load regime. More broadly, our work illustrates how in vivo functions of motors can be dissected by manipulating their mechanical properties.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 10","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11215527/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141468236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07Epub Date: 2024-07-15DOI: 10.1083/jcb.202402035
Kieop Park, Aastha Garde, Siddharthan B Thendral, Adam W J Soh, Qiuyi Chi, David R Sherwood
To breach the basement membrane, cells in development and cancer use large, transient, specialized lipid-rich membrane protrusions. Using live imaging, endogenous protein tagging, and cell-specific RNAi during Caenorhabditis elegans anchor cell (AC) invasion, we demonstrate that the lipogenic SREBP transcription factor SBP-1 drives the expression of the fatty acid synthesis enzymes POD-2 and FASN-1 prior to invasion. We show that phospholipid-producing LPIN-1 and sphingomyelin synthase SMS-1, which use fatty acids as substrates, produce lysosome stores that build the AC's invasive protrusion, and that SMS-1 also promotes protrusion localization of the lipid raft partitioning ZMP-1 matrix metalloproteinase. Finally, we discover that HMG-CoA reductase HMGR-1, which generates isoprenoids for prenylation, localizes to the ER and enriches in peroxisomes at the AC invasive front, and that the final transmembrane prenylation enzyme, ICMT-1, localizes to endoplasmic reticulum exit sites that dynamically polarize to deliver prenylated GTPases for protrusion formation. Together, these results reveal a collaboration between lipogenesis and a polarized lipid prenylation system that drives invasive protrusion formation.
为了突破基底膜,细胞在发育和癌变过程中会使用大型、瞬时、特化的富脂膜突起。在秀丽隐杆线虫锚细胞(AC)入侵过程中,我们利用实时成像、内源蛋白标记和细胞特异性 RNAi 技术证明,在入侵之前,脂质生成 SREBP 转录因子 SBP-1 驱动脂肪酸合成酶 POD-2 和 FASN-1 的表达。我们还发现,以脂肪酸为底物的磷脂生产酶 LPIN-1 和鞘磷脂合成酶 SMS-1,可产生溶酶体储存,从而构建 AC 的侵袭性突起,SMS-1 还可促进脂筏分区 ZMP-1 基质金属蛋白酶的突起定位。最后,我们发现,HMG-CoA 还原酶 HMGR-1 能生成用于前炔化的异丙肾上腺素,它能定位到 ER 并富集在 AC 侵袭前沿的过氧物酶体中,最后一种跨膜前炔化酶 ICMT-1 能定位到内质网出口位点,这些位点能动态极化,为突起的形成提供前炔化 GTP 酶。这些结果共同揭示了脂肪生成与极化脂质前酰化系统之间的协作,这种协作推动了侵袭性突起的形成。
{"title":"De novo lipid synthesis and polarized prenylation drive cell invasion through basement membrane.","authors":"Kieop Park, Aastha Garde, Siddharthan B Thendral, Adam W J Soh, Qiuyi Chi, David R Sherwood","doi":"10.1083/jcb.202402035","DOIUrl":"10.1083/jcb.202402035","url":null,"abstract":"<p><p>To breach the basement membrane, cells in development and cancer use large, transient, specialized lipid-rich membrane protrusions. Using live imaging, endogenous protein tagging, and cell-specific RNAi during Caenorhabditis elegans anchor cell (AC) invasion, we demonstrate that the lipogenic SREBP transcription factor SBP-1 drives the expression of the fatty acid synthesis enzymes POD-2 and FASN-1 prior to invasion. We show that phospholipid-producing LPIN-1 and sphingomyelin synthase SMS-1, which use fatty acids as substrates, produce lysosome stores that build the AC's invasive protrusion, and that SMS-1 also promotes protrusion localization of the lipid raft partitioning ZMP-1 matrix metalloproteinase. Finally, we discover that HMG-CoA reductase HMGR-1, which generates isoprenoids for prenylation, localizes to the ER and enriches in peroxisomes at the AC invasive front, and that the final transmembrane prenylation enzyme, ICMT-1, localizes to endoplasmic reticulum exit sites that dynamically polarize to deliver prenylated GTPases for protrusion formation. Together, these results reveal a collaboration between lipogenesis and a polarized lipid prenylation system that drives invasive protrusion formation.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 10","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11248228/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141616523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07Epub Date: 2024-06-27DOI: 10.1083/jcb.202403115
Rebecca Tam, Tony J C Harris
Regulated cell shape change requires the induction of cortical cytoskeletal domains. Often, local changes to plasma membrane (PM) topography are involved. Centrosomes organize cortical domains and can affect PM topography by locally pulling the PM inward. Are these centrosome effects coupled? At the syncytial Drosophila embryo cortex, centrosome-induced actin caps grow into dome-like compartments for mitoses. We found the nascent cap to be a collection of PM folds and tubules formed over the astral centrosomal MT array. The localized infoldings require centrosome and dynein activities, and myosin-based surface tension prevents them elsewhere. Centrosome-engaged PM infoldings become specifically enriched with an Arp2/3 induction pathway. Arp2/3 actin network growth between the infoldings counterbalances centrosomal pulling forces and disperses the folds for actin cap expansion. Abnormal domain topography with either centrosome or Arp2/3 disruption correlates with decreased exocytic vesicle association. Together, our data implicate centrosome-organized PM infoldings in coordinating Arp2/3 network growth and exocytosis for cortical domain assembly.
{"title":"Centrosome-organized plasma membrane infoldings linked to growth of a cortical actin domain.","authors":"Rebecca Tam, Tony J C Harris","doi":"10.1083/jcb.202403115","DOIUrl":"10.1083/jcb.202403115","url":null,"abstract":"<p><p>Regulated cell shape change requires the induction of cortical cytoskeletal domains. Often, local changes to plasma membrane (PM) topography are involved. Centrosomes organize cortical domains and can affect PM topography by locally pulling the PM inward. Are these centrosome effects coupled? At the syncytial Drosophila embryo cortex, centrosome-induced actin caps grow into dome-like compartments for mitoses. We found the nascent cap to be a collection of PM folds and tubules formed over the astral centrosomal MT array. The localized infoldings require centrosome and dynein activities, and myosin-based surface tension prevents them elsewhere. Centrosome-engaged PM infoldings become specifically enriched with an Arp2/3 induction pathway. Arp2/3 actin network growth between the infoldings counterbalances centrosomal pulling forces and disperses the folds for actin cap expansion. Abnormal domain topography with either centrosome or Arp2/3 disruption correlates with decreased exocytic vesicle association. Together, our data implicate centrosome-organized PM infoldings in coordinating Arp2/3 network growth and exocytosis for cortical domain assembly.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 10","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11215285/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141457101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07Epub Date: 2024-07-05DOI: 10.1083/jcb.202312069
Jonathan T Vu, Katherine U Tavasoli, Connor J Sheedy, Soham P Chowdhury, Lori Mandjikian, Julien Bacal, Meghan A Morrissey, Chris D Richardson, Brooke M Gardner
Peroxisomes are membrane-bound organelles harboring metabolic enzymes. In humans, peroxisomes are required for normal development, yet the genes regulating peroxisome function remain unclear. We performed a genome-wide CRISPRi screen to identify novel factors involved in peroxisomal homeostasis. We found that inhibition of RNF146, an E3 ligase activated by poly(ADP-ribose), reduced the import of proteins into peroxisomes. RNF146-mediated loss of peroxisome import depended on the stabilization and activity of the poly(ADP-ribose) polymerases TNKS and TNKS2, which bind the peroxisomal membrane protein PEX14. We propose that RNF146 and TNKS/2 regulate peroxisome import efficiency by PARsylation of proteins at the peroxisome membrane. Interestingly, we found that the loss of peroxisomes increased TNKS/2 and RNF146-dependent degradation of non-peroxisomal substrates, including the β-catenin destruction complex component AXIN1, which was sufficient to alter the amplitude of β-catenin transcription. Together, these observations not only suggest previously undescribed roles for RNF146 in peroxisomal regulation but also a novel role in bridging peroxisome function with Wnt/β-catenin signaling during development.
{"title":"A genome-wide screen links peroxisome regulation with Wnt signaling through RNF146 and TNKS/2.","authors":"Jonathan T Vu, Katherine U Tavasoli, Connor J Sheedy, Soham P Chowdhury, Lori Mandjikian, Julien Bacal, Meghan A Morrissey, Chris D Richardson, Brooke M Gardner","doi":"10.1083/jcb.202312069","DOIUrl":"10.1083/jcb.202312069","url":null,"abstract":"<p><p>Peroxisomes are membrane-bound organelles harboring metabolic enzymes. In humans, peroxisomes are required for normal development, yet the genes regulating peroxisome function remain unclear. We performed a genome-wide CRISPRi screen to identify novel factors involved in peroxisomal homeostasis. We found that inhibition of RNF146, an E3 ligase activated by poly(ADP-ribose), reduced the import of proteins into peroxisomes. RNF146-mediated loss of peroxisome import depended on the stabilization and activity of the poly(ADP-ribose) polymerases TNKS and TNKS2, which bind the peroxisomal membrane protein PEX14. We propose that RNF146 and TNKS/2 regulate peroxisome import efficiency by PARsylation of proteins at the peroxisome membrane. Interestingly, we found that the loss of peroxisomes increased TNKS/2 and RNF146-dependent degradation of non-peroxisomal substrates, including the β-catenin destruction complex component AXIN1, which was sufficient to alter the amplitude of β-catenin transcription. Together, these observations not only suggest previously undescribed roles for RNF146 in peroxisomal regulation but also a novel role in bridging peroxisome function with Wnt/β-catenin signaling during development.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 10","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11223164/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141534524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07Epub Date: 2024-08-08DOI: 10.1083/jcb.202401024
Eline C Brombacher, Thiago A Patente, Alwin J van der Ham, Tijmen J A Moll, Frank Otto, Fenne W M Verheijen, Esther A Zaal, Arnoud H de Ru, Rayman T N Tjokrodirijo, Celia R Berkers, Peter A van Veelen, Bruno Guigas, Bart Everts
Dendritic cell (DC) activation and function are underpinned by profound changes in cellular metabolism. Several studies indicate that the ability of DCs to promote tolerance is dependent on catabolic metabolism. Yet the contribution of AMP-activated kinase (AMPK), a central energy sensor promoting catabolism, to DC tolerogenicity remains unknown. Here, we show that AMPK activation renders human monocyte-derived DCs tolerogenic as evidenced by an enhanced ability to drive differentiation of regulatory T cells, a process dependent on increased RALDH activity. This is accompanied by several metabolic changes, including increased breakdown of glycerophospholipids, enhanced mitochondrial fission-dependent fatty acid oxidation, and upregulated glucose catabolism. This metabolic rewiring is functionally important as we found interference with these metabolic processes to reduce to various degrees AMPK-induced RALDH activity as well as the tolerogenic capacity of moDCs. Altogether, our findings reveal a key role for AMPK signaling in shaping DC tolerogenicity and suggest AMPK as a target to direct DC-driven tolerogenic responses in therapeutic settings.
树突状细胞(DC)的活化和功能是由细胞代谢的深刻变化支撑的。一些研究表明,树突状细胞促进耐受的能力取决于分解代谢。然而,促进新陈代谢的中心能量传感器 AMPK 对 DC 耐受性的贡献仍然未知。在这里,我们发现 AMPK 激活可使人类单核细胞衍生的 DC 产生耐受性,这表现在驱动调节性 T 细胞分化的能力增强,而这一过程依赖于 RALDH 活性的增加。与此同时,新陈代谢也发生了一些变化,包括甘油磷脂分解增加、线粒体裂变依赖性脂肪酸氧化增强以及葡萄糖分解代谢上调。这种代谢重构在功能上非常重要,因为我们发现干扰这些代谢过程会在不同程度上降低 AMPK 诱导的 RALDH 活性以及 moDCs 的耐受能力。总之,我们的研究结果揭示了 AMPK 信号在形成直流耐受性中的关键作用,并建议将 AMPK 作为治疗环境中指导直流驱动的耐受性反应的靶点。
{"title":"AMPK activation induces RALDH+ tolerogenic dendritic cells by rewiring glucose and lipid metabolism.","authors":"Eline C Brombacher, Thiago A Patente, Alwin J van der Ham, Tijmen J A Moll, Frank Otto, Fenne W M Verheijen, Esther A Zaal, Arnoud H de Ru, Rayman T N Tjokrodirijo, Celia R Berkers, Peter A van Veelen, Bruno Guigas, Bart Everts","doi":"10.1083/jcb.202401024","DOIUrl":"10.1083/jcb.202401024","url":null,"abstract":"<p><p>Dendritic cell (DC) activation and function are underpinned by profound changes in cellular metabolism. Several studies indicate that the ability of DCs to promote tolerance is dependent on catabolic metabolism. Yet the contribution of AMP-activated kinase (AMPK), a central energy sensor promoting catabolism, to DC tolerogenicity remains unknown. Here, we show that AMPK activation renders human monocyte-derived DCs tolerogenic as evidenced by an enhanced ability to drive differentiation of regulatory T cells, a process dependent on increased RALDH activity. This is accompanied by several metabolic changes, including increased breakdown of glycerophospholipids, enhanced mitochondrial fission-dependent fatty acid oxidation, and upregulated glucose catabolism. This metabolic rewiring is functionally important as we found interference with these metabolic processes to reduce to various degrees AMPK-induced RALDH activity as well as the tolerogenic capacity of moDCs. Altogether, our findings reveal a key role for AMPK signaling in shaping DC tolerogenicity and suggest AMPK as a target to direct DC-driven tolerogenic responses in therapeutic settings.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 10","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11310580/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141901861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07Epub Date: 2024-07-30DOI: 10.1083/jcb.202401140
Gabriel Escobedo, Yu Wu, Yuki Ogawa, Xiaoyun Ding, Matthew N Rasband
The evolution of ion channel clustering at nodes of Ranvier enabled the development of complex vertebrate nervous systems. At mammalian nodes, the K+ leak channels TRAAK and TREK-1 underlie membrane repolarization. Despite the molecular similarities between nodes and the axon initial segment (AIS), TRAAK and TREK-1 are reportedly node-specific, suggesting a unique clustering mechanism. However, we show that TRAAK and TREK-1 are enriched at both nodes and AIS through a common mechanism. We identified a motif near the C-terminus of TRAAK that is necessary and sufficient for its clustering. The motif first evolved among cartilaginous fish. Using AnkyrinG (AnkG) conditional knockout mice, CRISPR/Cas9-mediated disruption of AnkG, co-immunoprecipitation, and surface recruitment assays, we show that TRAAK forms a complex with AnkG and that AnkG is necessary for TRAAK's AIS and nodal clustering. In contrast, TREK-1's clustering requires TRAAK. Our results expand the repertoire of AIS and nodal ion channel clustering mechanisms and emphasize AnkG's central role in assembling excitable domains.
{"title":"An evolutionarily conserved AnkyrinG-dependent motif clusters axonal K2P K+ channels.","authors":"Gabriel Escobedo, Yu Wu, Yuki Ogawa, Xiaoyun Ding, Matthew N Rasband","doi":"10.1083/jcb.202401140","DOIUrl":"10.1083/jcb.202401140","url":null,"abstract":"<p><p>The evolution of ion channel clustering at nodes of Ranvier enabled the development of complex vertebrate nervous systems. At mammalian nodes, the K+ leak channels TRAAK and TREK-1 underlie membrane repolarization. Despite the molecular similarities between nodes and the axon initial segment (AIS), TRAAK and TREK-1 are reportedly node-specific, suggesting a unique clustering mechanism. However, we show that TRAAK and TREK-1 are enriched at both nodes and AIS through a common mechanism. We identified a motif near the C-terminus of TRAAK that is necessary and sufficient for its clustering. The motif first evolved among cartilaginous fish. Using AnkyrinG (AnkG) conditional knockout mice, CRISPR/Cas9-mediated disruption of AnkG, co-immunoprecipitation, and surface recruitment assays, we show that TRAAK forms a complex with AnkG and that AnkG is necessary for TRAAK's AIS and nodal clustering. In contrast, TREK-1's clustering requires TRAAK. Our results expand the repertoire of AIS and nodal ion channel clustering mechanisms and emphasize AnkG's central role in assembling excitable domains.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 10","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11289519/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141792525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}