Pub Date : 2024-12-02Epub Date: 2024-11-15DOI: 10.1083/jcb.202410205
Axel Mogk, Fabian den Brave
Mogk and den Brave discuss exciting results from a comprehensive screen of heat shock response components in yeast, published in this issue by Pincus and colleagues (https://doi.org/10.1083/jcb.202401082). Their work reveals modulatory regulatory loops that fine-tune the timing of the shutdown of this highly conserved pathway.
Mogk 和 den Brave 讨论了 Pincus 及其同事在本期(https://doi.org/10.1083/jcb.202401082)上发表的全面筛选酵母热休克反应成分的令人兴奋的结果。他们的工作揭示了微调这一高度保守途径关闭时机的调节环路。
{"title":"Fine-tuning stress responses by auxiliary feedback loops that sense damage repair.","authors":"Axel Mogk, Fabian den Brave","doi":"10.1083/jcb.202410205","DOIUrl":"10.1083/jcb.202410205","url":null,"abstract":"<p><p>Mogk and den Brave discuss exciting results from a comprehensive screen of heat shock response components in yeast, published in this issue by Pincus and colleagues (https://doi.org/10.1083/jcb.202401082). Their work reveals modulatory regulatory loops that fine-tune the timing of the shutdown of this highly conserved pathway.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 12","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11572479/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142638690","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 : 2024-12-02Epub Date: 2024-09-30DOI: 10.1083/jcb.202403195
Takami Sho, Ying Li, Haifeng Jiao, Li Yu
Lysosomes, essential for intracellular degradation and recycling, employ damage-control strategies such as lysophagy and membrane repair mechanisms to maintain functionality and cellular homeostasis. Our study unveils migratory autolysosome disposal (MAD), a response to lysosomal damage where cells expel LAMP1-LC3 positive structures via autolysosome exocytosis, requiring autophagy machinery, SNARE proteins, and cell migration. This mechanism, crucial for mitigating lysosomal damage, underscores the role of cell migration in lysosome damage control and facilitates the release of small extracellular vesicles, highlighting the intricate relationship between cell migration, organelle quality control, and extracellular vesicle release.
{"title":"Migratory autolysosome disposal mitigates lysosome damage.","authors":"Takami Sho, Ying Li, Haifeng Jiao, Li Yu","doi":"10.1083/jcb.202403195","DOIUrl":"10.1083/jcb.202403195","url":null,"abstract":"<p><p>Lysosomes, essential for intracellular degradation and recycling, employ damage-control strategies such as lysophagy and membrane repair mechanisms to maintain functionality and cellular homeostasis. Our study unveils migratory autolysosome disposal (MAD), a response to lysosomal damage where cells expel LAMP1-LC3 positive structures via autolysosome exocytosis, requiring autophagy machinery, SNARE proteins, and cell migration. This mechanism, crucial for mitigating lysosomal damage, underscores the role of cell migration in lysosome damage control and facilitates the release of small extracellular vesicles, highlighting the intricate relationship between cell migration, organelle quality control, and extracellular vesicle release.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 12","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11457477/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142347298","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 : 2024-12-02Epub Date: 2024-11-15DOI: 10.1083/jcb.202407123
Asif Ali, Sarah Paracha, David Pincus
Most eukaryotic genes encode polypeptides that are either obligate members of hetero-stoichiometric complexes or clients of organelle-targeting pathways. Proteins in these classes can be released from the ribosome as "orphans"-newly synthesized proteins not associated with their stoichiometric binding partner(s) and/or not targeted to their destination organelle. Here we integrate recent findings suggesting that although cells selectively degrade orphan proteins under homeostatic conditions, they can preserve them in chaperone-regulated biomolecular condensates during stress. These orphan protein condensates activate the heat shock response (HSR) and represent subcellular sites where the chaperones induced by the HSR execute their functions. Reversible condensation of orphan proteins may broadly safeguard labile precursors during stress.
{"title":"Preserve or destroy: Orphan protein proteostasis and the heat shock response.","authors":"Asif Ali, Sarah Paracha, David Pincus","doi":"10.1083/jcb.202407123","DOIUrl":"10.1083/jcb.202407123","url":null,"abstract":"<p><p>Most eukaryotic genes encode polypeptides that are either obligate members of hetero-stoichiometric complexes or clients of organelle-targeting pathways. Proteins in these classes can be released from the ribosome as \"orphans\"-newly synthesized proteins not associated with their stoichiometric binding partner(s) and/or not targeted to their destination organelle. Here we integrate recent findings suggesting that although cells selectively degrade orphan proteins under homeostatic conditions, they can preserve them in chaperone-regulated biomolecular condensates during stress. These orphan protein condensates activate the heat shock response (HSR) and represent subcellular sites where the chaperones induced by the HSR execute their functions. Reversible condensation of orphan proteins may broadly safeguard labile precursors during stress.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 12","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11572482/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142638711","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 : 2024-11-04Epub Date: 2024-08-13DOI: 10.1083/jcb.202307035
Zachary N Wilson, Matt West, Alyssa M English, Greg Odorizzi, Adam L Hughes
Preserving the health of the mitochondrial network is critical to cell viability and longevity. To do so, mitochondria employ several membrane remodeling mechanisms, including the formation of mitochondrial-derived vesicles (MDVs) and compartments (MDCs) to selectively remove portions of the organelle. In contrast to well-characterized MDVs, the distinguishing features of MDC formation and composition remain unclear. Here, we used electron tomography to observe that MDCs form as large, multilamellar domains that generate concentric spherical compartments emerging from mitochondrial tubules at ER-mitochondria contact sites. Time-lapse fluorescence microscopy of MDC biogenesis revealed that mitochondrial membrane extensions repeatedly elongate, coalesce, and invaginate to form these compartments that encase multiple layers of membrane. As such, MDCs strongly sequester portions of the outer mitochondrial membrane, securing membrane cargo into a protected domain, while also enclosing cytosolic material within the MDC lumen. Collectively, our results provide a model for MDC formation and describe key features that distinguish MDCs from other previously identified mitochondrial structures and cargo-sorting domains.
{"title":"Mitochondrial-derived compartments are multilamellar domains that encase membrane cargo and cytosol.","authors":"Zachary N Wilson, Matt West, Alyssa M English, Greg Odorizzi, Adam L Hughes","doi":"10.1083/jcb.202307035","DOIUrl":"10.1083/jcb.202307035","url":null,"abstract":"<p><p>Preserving the health of the mitochondrial network is critical to cell viability and longevity. To do so, mitochondria employ several membrane remodeling mechanisms, including the formation of mitochondrial-derived vesicles (MDVs) and compartments (MDCs) to selectively remove portions of the organelle. In contrast to well-characterized MDVs, the distinguishing features of MDC formation and composition remain unclear. Here, we used electron tomography to observe that MDCs form as large, multilamellar domains that generate concentric spherical compartments emerging from mitochondrial tubules at ER-mitochondria contact sites. Time-lapse fluorescence microscopy of MDC biogenesis revealed that mitochondrial membrane extensions repeatedly elongate, coalesce, and invaginate to form these compartments that encase multiple layers of membrane. As such, MDCs strongly sequester portions of the outer mitochondrial membrane, securing membrane cargo into a protected domain, while also enclosing cytosolic material within the MDC lumen. Collectively, our results provide a model for MDC formation and describe key features that distinguish MDCs from other previously identified mitochondrial structures and cargo-sorting domains.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 11","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11320809/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141971159","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 : 2024-11-04Epub Date: 2024-08-19DOI: 10.1083/jcb.202311137
Ben Johnson, Maria Iuliano, TuKiet T Lam, Thomas Biederer, Pietro V De Camilli
Junctions between the ER and plasma membrane (PM) are implicated in calcium homeostasis, non-vesicular lipid transfer, and other cellular functions. Two ER proteins that function both as tethers to the PM via a polybasic C-terminus motif and as phospholipid transporters are brain-enriched TMEM24 (C2CD2L) and its paralog C2CD2. We report that both proteins also form a complex with band 4.1 family members, which in turn bind PM proteins including cell adhesion molecules such as SynCAM 1. This complex enriches TMEM24 and C2CD2 containing ER/PM junctions at sites of cell contacts. Dynamic properties of TMEM24-dependent ER/PM junctions are impacted when band 4.1 is part of the junction, as TMEM24 at cell-adjacent ER/PM junctions is not shed from the PM by calcium rise, unlike TMEM24 at non-cell adjacent junctions. Lipid transport between the ER and the PM by TMEM24 and C2CD2 at sites where cells, including neurons, contact other cells may participate in adaptive responses to cell contact-dependent signaling.
{"title":"A complex of the lipid transport ER proteins TMEM24 and C2CD2 with band 4.1 at cell-cell contacts.","authors":"Ben Johnson, Maria Iuliano, TuKiet T Lam, Thomas Biederer, Pietro V De Camilli","doi":"10.1083/jcb.202311137","DOIUrl":"10.1083/jcb.202311137","url":null,"abstract":"<p><p>Junctions between the ER and plasma membrane (PM) are implicated in calcium homeostasis, non-vesicular lipid transfer, and other cellular functions. Two ER proteins that function both as tethers to the PM via a polybasic C-terminus motif and as phospholipid transporters are brain-enriched TMEM24 (C2CD2L) and its paralog C2CD2. We report that both proteins also form a complex with band 4.1 family members, which in turn bind PM proteins including cell adhesion molecules such as SynCAM 1. This complex enriches TMEM24 and C2CD2 containing ER/PM junctions at sites of cell contacts. Dynamic properties of TMEM24-dependent ER/PM junctions are impacted when band 4.1 is part of the junction, as TMEM24 at cell-adjacent ER/PM junctions is not shed from the PM by calcium rise, unlike TMEM24 at non-cell adjacent junctions. Lipid transport between the ER and the PM by TMEM24 and C2CD2 at sites where cells, including neurons, contact other cells may participate in adaptive responses to cell contact-dependent signaling.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 11","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11334333/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142000012","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 : 2024-11-04Epub Date: 2024-08-06DOI: 10.1083/jcb.202308034
Pablo Lara-Gonzalez, Smriti Variyar, Shabnam Moghareh, Anh Cao Ngoc Nguyen, Amrutha Kizhedathu, Jacqueline Budrewicz, Aleesa Schlientz, Neha Varshney, Andrew Bellaart, Karen Oegema, Lee Bardwell, Arshad Desai
Mitosis in early embryos often proceeds at a rapid pace, but how this pace is achieved is not understood. Here, we show that cyclin B3 is the dominant driver of rapid embryonic mitoses in the C. elegans embryo. Cyclins B1 and B2 support slow mitosis (NEBD to anaphase ∼600 s), but the presence of cyclin B3 dominantly drives the approximately threefold faster mitosis observed in wildtype. Multiple mitotic events are slowed down in cyclin B1 and B2-driven mitosis, and cyclin B3-associated Cdk1 H1 kinase activity is ∼25-fold more active than cyclin B1-associated Cdk1. Addition of cyclin B1 to fast cyclin B3-only mitosis introduces an ∼60-s delay between completion of chromosome alignment and anaphase onset; this delay, which is important for segregation fidelity, is dependent on inhibitory phosphorylation of the anaphase activator Cdc20. Thus, cyclin B3 dominance, coupled to a cyclin B1-dependent delay that acts via Cdc20 phosphorylation, sets the rapid pace and ensures mitotic fidelity in the early C. elegans embryo.
{"title":"Cyclin B3 is a dominant fast-acting cyclin that drives rapid early embryonic mitoses.","authors":"Pablo Lara-Gonzalez, Smriti Variyar, Shabnam Moghareh, Anh Cao Ngoc Nguyen, Amrutha Kizhedathu, Jacqueline Budrewicz, Aleesa Schlientz, Neha Varshney, Andrew Bellaart, Karen Oegema, Lee Bardwell, Arshad Desai","doi":"10.1083/jcb.202308034","DOIUrl":"10.1083/jcb.202308034","url":null,"abstract":"<p><p>Mitosis in early embryos often proceeds at a rapid pace, but how this pace is achieved is not understood. Here, we show that cyclin B3 is the dominant driver of rapid embryonic mitoses in the C. elegans embryo. Cyclins B1 and B2 support slow mitosis (NEBD to anaphase ∼600 s), but the presence of cyclin B3 dominantly drives the approximately threefold faster mitosis observed in wildtype. Multiple mitotic events are slowed down in cyclin B1 and B2-driven mitosis, and cyclin B3-associated Cdk1 H1 kinase activity is ∼25-fold more active than cyclin B1-associated Cdk1. Addition of cyclin B1 to fast cyclin B3-only mitosis introduces an ∼60-s delay between completion of chromosome alignment and anaphase onset; this delay, which is important for segregation fidelity, is dependent on inhibitory phosphorylation of the anaphase activator Cdc20. Thus, cyclin B3 dominance, coupled to a cyclin B1-dependent delay that acts via Cdc20 phosphorylation, sets the rapid pace and ensures mitotic fidelity in the early C. elegans embryo.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 11","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11303871/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141893507","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 : 2024-11-04Epub Date: 2024-08-08DOI: 10.1083/jcb.202405032
Chuying Zhou, You Kure Wu, Fumiyoshi Ishidate, Takahiro K Fujiwara, Mineko Kengaku
Nuclear migration is critical for the proper positioning of neurons in the developing brain. It is known that bidirectional microtubule motors are required for nuclear transport, yet the mechanism of the coordination of opposing motors is still under debate. Using mouse cerebellar granule cells, we demonstrate that Nesprin-2 serves as a nucleus-motor adaptor, coordinating the interplay of kinesin-1 and dynein. Nesprin-2 recruits dynein-dynactin-BicD2 independently of the nearby kinesin-binding LEWD motif. Both motor binding sites are required to rescue nuclear migration defects caused by the loss of function of Nesprin-2. In an intracellular cargo transport assay, the Nesprin-2 fragment encompassing the motor binding sites generates persistent movements toward both microtubule minus and plus ends. Nesprin-2 drives bidirectional cargo movements over a prolonged period along perinuclear microtubules, which advance during the migration of neurons. We propose that Nesprin-2 keeps the nucleus mobile by coordinating opposing motors, enabling continuous nuclear transport along advancing microtubules in migrating cells.
{"title":"Nesprin-2 coordinates opposing microtubule motors during nuclear migration in neurons.","authors":"Chuying Zhou, You Kure Wu, Fumiyoshi Ishidate, Takahiro K Fujiwara, Mineko Kengaku","doi":"10.1083/jcb.202405032","DOIUrl":"10.1083/jcb.202405032","url":null,"abstract":"<p><p>Nuclear migration is critical for the proper positioning of neurons in the developing brain. It is known that bidirectional microtubule motors are required for nuclear transport, yet the mechanism of the coordination of opposing motors is still under debate. Using mouse cerebellar granule cells, we demonstrate that Nesprin-2 serves as a nucleus-motor adaptor, coordinating the interplay of kinesin-1 and dynein. Nesprin-2 recruits dynein-dynactin-BicD2 independently of the nearby kinesin-binding LEWD motif. Both motor binding sites are required to rescue nuclear migration defects caused by the loss of function of Nesprin-2. In an intracellular cargo transport assay, the Nesprin-2 fragment encompassing the motor binding sites generates persistent movements toward both microtubule minus and plus ends. Nesprin-2 drives bidirectional cargo movements over a prolonged period along perinuclear microtubules, which advance during the migration of neurons. We propose that Nesprin-2 keeps the nucleus mobile by coordinating opposing motors, enabling continuous nuclear transport along advancing microtubules in migrating cells.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 11","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11310688/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141901862","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 : 2024-11-04Epub Date: 2024-10-28DOI: 10.1083/jcb.202410007
Andreas Boland, Julia Kamenz
Racecar drivers use left-foot braking, i.e., simultaneously engaging brake and throttle, to carefully balance acceleration and traction when navigating chicanes. In this issue, Lara-Gonzalez et al. (https://doi.org/10.1083/jcb.202308034) show that C. elegans embryos employ the molecular equivalent of left-foot braking to faithfully speed through mitosis.
{"title":"Racing through C. elegans mitosis using cyclin B3.","authors":"Andreas Boland, Julia Kamenz","doi":"10.1083/jcb.202410007","DOIUrl":"10.1083/jcb.202410007","url":null,"abstract":"<p><p>Racecar drivers use left-foot braking, i.e., simultaneously engaging brake and throttle, to carefully balance acceleration and traction when navigating chicanes. In this issue, Lara-Gonzalez et al. (https://doi.org/10.1083/jcb.202308034) show that C. elegans embryos employ the molecular equivalent of left-foot braking to faithfully speed through mitosis.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 11","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11519320/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142501093","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 : 2024-11-04Epub Date: 2024-10-14DOI: 10.1083/jcb.202409044
Hide A Konishi, Hironori Funabiki
Chromosomes undergo dramatic compaction during mitosis, but accurately measuring their volume has been challenging. Employing serial block face scanning electron microscopy, Cisneros-Soberanis et al. (https://doi.org/10.1083/jcb.202403165) report that mitotic chromosomes compact to a nucleosome concentration of ∼760 µM.
{"title":"How condensed are mitotic chromosomes?","authors":"Hide A Konishi, Hironori Funabiki","doi":"10.1083/jcb.202409044","DOIUrl":"https://doi.org/10.1083/jcb.202409044","url":null,"abstract":"<p><p>Chromosomes undergo dramatic compaction during mitosis, but accurately measuring their volume has been challenging. Employing serial block face scanning electron microscopy, Cisneros-Soberanis et al. (https://doi.org/10.1083/jcb.202403165) report that mitotic chromosomes compact to a nucleosome concentration of ∼760 µM.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 11","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11473595/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142466349","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 : 2024-11-04Epub Date: 2024-08-13DOI: 10.1083/jcb.202307036
Zachary N Wilson, Sai Sangeetha Balasubramaniam, Sara Wong, Max-Hinderk Schuler, Mitchell J Wopat, Adam L Hughes
The outer mitochondrial membrane (OMM) creates a boundary that imports most of the mitochondrial proteome while removing extraneous or damaged proteins. How the OMM senses aberrant proteins and remodels to maintain OMM integrity remains unresolved. Previously, we identified a mitochondrial remodeling mechanism called the mitochondrial-derived compartment (MDC) that removes a subset of the mitochondrial proteome. Here, we show that MDCs specifically sequester proteins localized only at the OMM, providing an explanation for how select mitochondrial proteins are incorporated into MDCs. Remarkably, selective sorting into MDCs also occurs within the OMM, as subunits of the translocase of the outer membrane (TOM) complex are excluded from MDCs unless assembly of the TOM complex is impaired. Considering that overloading the OMM with mitochondrial membrane proteins or mistargeted tail-anchored membrane proteins induces MDCs to form and sequester these proteins, we propose that one functional role of MDCs is to create an OMM-enriched trap that segregates and sequesters excess proteins from the mitochondrial surface.
{"title":"Mitochondrial-derived compartments remove surplus proteins from the outer mitochondrial membrane.","authors":"Zachary N Wilson, Sai Sangeetha Balasubramaniam, Sara Wong, Max-Hinderk Schuler, Mitchell J Wopat, Adam L Hughes","doi":"10.1083/jcb.202307036","DOIUrl":"10.1083/jcb.202307036","url":null,"abstract":"<p><p>The outer mitochondrial membrane (OMM) creates a boundary that imports most of the mitochondrial proteome while removing extraneous or damaged proteins. How the OMM senses aberrant proteins and remodels to maintain OMM integrity remains unresolved. Previously, we identified a mitochondrial remodeling mechanism called the mitochondrial-derived compartment (MDC) that removes a subset of the mitochondrial proteome. Here, we show that MDCs specifically sequester proteins localized only at the OMM, providing an explanation for how select mitochondrial proteins are incorporated into MDCs. Remarkably, selective sorting into MDCs also occurs within the OMM, as subunits of the translocase of the outer membrane (TOM) complex are excluded from MDCs unless assembly of the TOM complex is impaired. Considering that overloading the OMM with mitochondrial membrane proteins or mistargeted tail-anchored membrane proteins induces MDCs to form and sequester these proteins, we propose that one functional role of MDCs is to create an OMM-enriched trap that segregates and sequesters excess proteins from the mitochondrial surface.</p>","PeriodicalId":15211,"journal":{"name":"Journal of Cell Biology","volume":"223 11","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11320589/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141971160","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}