The Journal of Cell Biology最新文献_第10页

Phosphorylation-dependent mitotic SUMOylation drives nuclear envelope-chromatin interactions. 磷酸化依赖的有丝分裂summoylation驱动核包膜-染色质相互作用。

IF 7.8

The Journal of Cell Biology Pub Date : 2021-12-06 Epub Date: 2021-11-17 DOI: 10.1083/jcb.202103036

Christopher Ptak, Natasha O Saik, Ashwini Premashankar, Diego L Lapetina, John D Aitchison, Ben Montpetit, Richard W Wozniak

{"title":"Phosphorylation-dependent mitotic SUMOylation drives nuclear envelope-chromatin interactions.","authors":"Christopher Ptak, Natasha O Saik, Ashwini Premashankar, Diego L Lapetina, John D Aitchison, Ben Montpetit, Richard W Wozniak","doi":"10.1083/jcb.202103036","DOIUrl":"https://doi.org/10.1083/jcb.202103036","url":null,"abstract":"In eukaryotes, chromatin binding to the inner nuclear membrane (INM) and nuclear pore complexes (NPCs) contributes to spatial organization of the genome and epigenetic programs important for gene expression. In mitosis, chromatin-nuclear envelope (NE) interactions are lost and then formed again as sister chromosomes segregate to postmitotic nuclei. Investigating these processes in S. cerevisiae, we identified temporally and spatially controlled phosphorylation-dependent SUMOylation events that positively regulate postmetaphase chromatin association with the NE. Our work establishes a phosphorylation-mediated targeting mechanism of the SUMO ligase Siz2 to the INM during mitosis, where Siz2 binds to and SUMOylates the VAP protein Scs2. The recruitment of Siz2 through Scs2 is further responsible for a wave of SUMOylation along the INM that supports the assembly and anchorage of subtelomeric chromatin at the INM and localization of an active gene (INO1) to NPCs during the later stages of mitosis and into G1-phase.","PeriodicalId":343306,"journal":{"name":"The Journal of Cell Biology","volume":" ","pages":""},"PeriodicalIF":7.8,"publicationDate":"2021-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/87/5f/JCB_202103036.PMC8641411.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39740573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Ubiquitylation by Rab40b/Cul5 regulates Rap2 localization and activity during cell migration Rab40b/Cul5的泛素化调节Rap2在细胞迁移过程中的定位和活性

The Journal of Cell Biology Pub Date : 2021-12-06 DOI: 10.1101/2021.12.06.471477

Emily D. Duncan, Ke-jun Han, Margaret A. Trout, R. Prekeris

{"title":"Ubiquitylation by Rab40b/Cul5 regulates Rap2 localization and activity during cell migration","authors":"Emily D. Duncan, Ke-jun Han, Margaret A. Trout, R. Prekeris","doi":"10.1101/2021.12.06.471477","DOIUrl":"https://doi.org/10.1101/2021.12.06.471477","url":null,"abstract":"Cell migration is a complex process that involves coordinated changes in membrane transport, actin cytoskeleton dynamics, and extracellular matrix remodeling. Ras-like small monomeric GTPases, such as Rap2, play a key role in regulating actin cytoskeleton dynamics and cell adhesions. However, how Rap2 function, localization, and activation are regulated during cell migration is not fully understood. We previously identified the small GTPase Rab40b as a regulator of breast cancer cell migration. Rab40b contains a Suppressor of Cytokine Signaling (SOCS) box, which facilitates binding to Cullin5, a known E3 Ubiquitin Ligase component responsible for protein ubiquitylation. In this study, we show that the Rab40b/Cullin5 complex ubiquitylates Rap2. Importantly, we demonstrate that ubiquitylation regulates Rap2 activation, as well as recycling of Rap2 from the endolysosomal compartment to the lamellipodia of migrating breast cancer cells. Based on these data, we propose that Rab40b/Cullin5 ubiquitylates and regulates Rap2-dependent actin dynamics at the leading-edge, a process that is required for breast cancer cell migration and invasion. SUMMARY The Rab40b/Cul5 complex is an emerging pro-migratory molecular machine. Duncan et al. identify the small GTPase Rap2 as a substrate of the Rab40b/Cul5 complex. They provide evidence that Rab40b/Cul5 ubiquitylates Rap2 to regulate its localization and activity during breast cancer cell migration, ultimately proposing a model by which Rap2 is targeted to the leading-edge plasma membrane to regulate actin dynamics during cell migration.","PeriodicalId":343306,"journal":{"name":"The Journal of Cell Biology","volume":"132 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133673479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

iASPP contributes to cell cortex rigidity, mitotic cell rounding, and spindle positioning. iASPP有助于细胞皮层的刚性，有丝分裂细胞的圆和纺锤体定位。

IF 7.8

The Journal of Cell Biology Pub Date : 2021-12-06 Epub Date: 2021-10-27 DOI: 10.1083/jcb.202012002

Aurélie Mangon, Danièle Salaün, Mohamed Lala Bouali, Mira Kuzmić, Sabine Quitard, Sylvie Thuault, Daniel Isnardon, Stéphane Audebert, Pierre-Henri Puech, Pascal Verdier-Pinard, Ali Badache

{"title":"iASPP contributes to cell cortex rigidity, mitotic cell rounding, and spindle positioning.","authors":"Aurélie Mangon, Danièle Salaün, Mohamed Lala Bouali, Mira Kuzmić, Sabine Quitard, Sylvie Thuault, Daniel Isnardon, Stéphane Audebert, Pierre-Henri Puech, Pascal Verdier-Pinard, Ali Badache","doi":"10.1083/jcb.202012002","DOIUrl":"https://doi.org/10.1083/jcb.202012002","url":null,"abstract":"iASPP is a protein mostly known as an inhibitor of p53 pro-apoptotic activity and a predicted regulatory subunit of the PP1 phosphatase, which is often overexpressed in tumors. We report that iASPP associates with the microtubule plus-end binding protein EB1, a central regulator of microtubule dynamics, via an SxIP motif. iASPP silencing or mutation of the SxIP motif led to defective microtubule capture at the cortex of mitotic cells, leading to abnormal positioning of the mitotic spindle. These effects were recapitulated by the knockdown of the membrane-to-cortex linker Myosin-Ic (Myo1c), which we identified as a novel partner of iASPP. Moreover, iASPP or Myo1c knockdown cells failed to round up upon mitosis because of defective cortical stiffness. We propose that by increasing cortical rigidity, iASPP helps cancer cells maintain a spherical geometry suitable for proper mitotic spindle positioning and chromosome partitioning.","PeriodicalId":343306,"journal":{"name":"The Journal of Cell Biology","volume":" ","pages":""},"PeriodicalIF":7.8,"publicationDate":"2021-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/a6/d0/JCB_202012002.PMC8562848.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39565675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Bidirectional regulation of calcium release-activated calcium (CRAC) channel by SARAF. SARAF对钙释放活化钙(CRAC)通道的双向调控。

IF 7.8

The Journal of Cell Biology Pub Date : 2021-12-06 Epub Date: 2021-10-27 DOI: 10.1083/jcb.202104007

Elia Zomot, Hadas Achildiev Cohen, Inbal Dagan, Ruslana Militsin, Raz Palty

{"title":"Bidirectional regulation of calcium release-activated calcium (CRAC) channel by SARAF.","authors":"Elia Zomot, Hadas Achildiev Cohen, Inbal Dagan, Ruslana Militsin, Raz Palty","doi":"10.1083/jcb.202104007","DOIUrl":"https://doi.org/10.1083/jcb.202104007","url":null,"abstract":"Store-operated calcium entry (SOCE) through the Ca2+ release-activated Ca2+ (CRAC) channel is a central mechanism by which cells generate Ca2+ signals and mediate Ca2+-dependent gene expression. The molecular basis for CRAC channel regulation by the SOCE-associated regulatory factor (SARAF) remained insufficiently understood. Here we found that following ER Ca2+ depletion, SARAF facilitates a conformational change in the ER Ca2+ sensor STIM1 that relieves an activation constraint enforced by the STIM1 inactivation domain (ID; aa 475-483) and promotes initial activation of STIM1, its translocation to ER-plasma membrane junctions, and coupling to Orai1 channels. Following intracellular Ca2+ rise, cooperation between SARAF and the STIM1 ID controls CRAC channel slow Ca2+-dependent inactivation. We further show that in T lymphocytes, SARAF is required for proper T cell receptor evoked transcription. Taking all these data together, we uncover a dual regulatory role for SARAF during both activation and inactivation of CRAC channels and show that SARAF fine-tunes intracellular Ca2+ responses and downstream gene expression in cells.","PeriodicalId":343306,"journal":{"name":"The Journal of Cell Biology","volume":" ","pages":""},"PeriodicalIF":7.8,"publicationDate":"2021-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/84/e8/JCB_202104007.PMC8562847.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39565676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Signaling by the integrated stress response kinase PKR is fine-tuned by dynamic clustering 综合应激反应激酶PKR的信号通过动态聚类进行微调

The Journal of Cell Biology Pub Date : 2021-11-22 DOI: 10.1083/jcb.202111100

F. Zappa, N. Muniozguren, J. C. Ponce-Rojas, D. Acosta-Alvear

引用次数: 14

Regulating peroxisome–ER contacts via the ACBD5-VAPB tether by FFAT motif phosphorylation and GSK3β 通过FFAT基序磷酸化和GSK3β通过ACBD5-VAPB系链调节过氧化物酶体-内质网接触

The Journal of Cell Biology Pub Date : 2021-11-12 DOI: 10.1101/2021.11.11.467785

Suzan Kors, Christian Hacker, C. Bolton, R. Maier, L. Reimann, Emily J.A. Kitchener, B. Warscheid, Joseph L. Costello, M. Schrader

{"title":"Regulating peroxisome–ER contacts via the ACBD5-VAPB tether by FFAT motif phosphorylation and GSK3β","authors":"Suzan Kors, Christian Hacker, C. Bolton, R. Maier, L. Reimann, Emily J.A. Kitchener, B. Warscheid, Joseph L. Costello, M. Schrader","doi":"10.1101/2021.11.11.467785","DOIUrl":"https://doi.org/10.1101/2021.11.11.467785","url":null,"abstract":"Peroxisomes and the endoplasmic reticulum (ER) cooperate in cellular lipid metabolism. They form membrane contacts through interaction of the peroxisomal membrane protein ACBD5 [acyl-coenzyme A-binding domain protein 5] and the ER-resident protein VAPB [vesicle-associated membrane protein-associated protein B]. ACBD5 binds to the major sperm protein domain of VAPB via its FFAT-like [two phenylalanines (FF) in an acidic tract] motif. However, molecular mechanisms, which regulate formation of these membrane contact sites, are unknown. Here, we reveal that peroxisome-ER associations via the ACBD5-VAPB tether are regulated by phosphorylation. We show that ACBD5-VAPB binding is phosphatase-sensitive and identify phosphorylation sites in the flanking regions and core of the FFAT-like motif, which alter interaction with VAPB and thus, peroxisome-ER contact sites differently. Moreover, we demonstrate that GSK3β [glycogen synthase kinase-3 beta] regulates this interaction. Our findings reveal for the first time a molecular mechanism for the regulation of peroxisome-ER contacts in mammalian cells and expand the current model of FFAT motifs and VAP interaction. SUMMARY Kors et al. reveal that peroxisome-ER associations via the ACBD5-VAPB tether are regulated by phosphorylation and GSK3β in mammalian cells. Phosphorylation sites in the FFAT-like motif of ACBD5 affect the binding to VAPB and thus, peroxisome-ER contact sites, differently.","PeriodicalId":343306,"journal":{"name":"The Journal of Cell Biology","volume":"632 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126913935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 17

ORP5 and ORP8 orchestrate lipid droplet biogenesis and maintenance at ER–mitochondria contact sites ORP5和ORP8在er -线粒体接触位点协调脂滴的形成和维持

The Journal of Cell Biology Pub Date : 2021-11-12 DOI: 10.1101/2021.11.11.468233

Valentin Guyard, V. F. Monteiro-Cardoso, Mohyeddine Omrane, Cécile Sauvanet, Audrey Houcine, C. Boulogne, Kalthoum Ben MBarek, N. Vitale, Orestis Facklaris, Naima El Khallouki, A. Thiam, F. Giordano

{"title":"ORP5 and ORP8 orchestrate lipid droplet biogenesis and maintenance at ER–mitochondria contact sites","authors":"Valentin Guyard, V. F. Monteiro-Cardoso, Mohyeddine Omrane, Cécile Sauvanet, Audrey Houcine, C. Boulogne, Kalthoum Ben MBarek, N. Vitale, Orestis Facklaris, Naima El Khallouki, A. Thiam, F. Giordano","doi":"10.1101/2021.11.11.468233","DOIUrl":"https://doi.org/10.1101/2021.11.11.468233","url":null,"abstract":"Lipid droplets (LDs) are the primary organelles of lipid storage, buffering energy fluctuations of the cell. They store neutral lipids in their core that is surrounded by a protein-decorated phospholipid monolayer. LDs arise from the Endoplasmic Reticulum (ER). The ER-protein seipin, localizing at ER-LD junctions, controls LD nucleation and growth. However, how LD biogenesis is spatially and temporally coordinated remains elusive. Here, we show that the lipid transfer proteins ORP5 and ORP8 control LD biogenesis at Mitochondria-Associated ER Membrane (MAM) subdomains, enriched in phosphatidic acid. We found that ORP5/8 regulate seipin recruitment to these MAM-LD contacts, and their loss impairs LD biogenesis. Importantly, the integrity of ER-mitochondria contact sites is crucial for the ORP5/8 function in regulating seipin-mediated LD biogenesis. Our study uncovers an unprecedented ORP5/8 role in orchestrating LD biogenesis at MAMs and brings novel insights into the metabolic crosstalk between mitochondria, ER, and LDs at membrane contact sites. HIGHLIGHTS ORP5 and ORP8 localize at MAM subdomains where LDs originate. Phosphatidic acid is enriched in MAM subdomains that are the birthplace of LDs. ORP5 and ORP8 knockdown impairs LD biogenesis. ORP5 and ORP8 regulate seipin recruitment to MAM-LD contact sites.","PeriodicalId":343306,"journal":{"name":"The Journal of Cell Biology","volume":"91 12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123115488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 19

Fbxo7 promotes Cdk6 activity to inhibit PFKP and glycolysis in T cells Fbxo7促进Cdk6活性抑制PFKP和T细胞糖酵解

The Journal of Cell Biology Pub Date : 2021-11-05 DOI: 10.1101/2021.11.05.467417

Rebecca Harris, Ming Yang, Christin Schmidt, Sarbjit Singh, A. Natarajan, C. Frezza, H. Laman

{"title":"Fbxo7 promotes Cdk6 activity to inhibit PFKP and glycolysis in T cells","authors":"Rebecca Harris, Ming Yang, Christin Schmidt, Sarbjit Singh, A. Natarajan, C. Frezza, H. Laman","doi":"10.1101/2021.11.05.467417","DOIUrl":"https://doi.org/10.1101/2021.11.05.467417","url":null,"abstract":"Deregulated Fbxo7 expression is associated with many pathologies, including anaemia, male sterility, cancer, and Parkinson’s disease, demonstrating its critical role in a variety of cell types. Although Fbxo7 is an F-box protein that recruits substrates for SCF-type E3 ubiquitin ligases, it also promotes the formation of cyclin D/Cdk6/p27 complexes in an E3-ligase independent fashion. We discovered PFKP, the major gatekeeper of glycolysis, in a screen for Fbxo7 substrates. PFKP has been previously shown to be a critical substrate of Cdk6 for the viability of T-ALL cells. We investigated the molecular relationships between Fbxo7, Cdk6 and PFKP, and the functional effect Fbxo7 has on T cell metabolism, viability, and activation. Fbxo7 promotes Cdk6-independent ubiquitination and Cdk6-dependent phosphorylation of PFKP. Importantly Fbxo7-deficient cells have reduced Cdk6 activity, and haematopoietic and lymphocytic cell lines show a significant dependency on Fbxo7. Compared to WT cells, CD4+ T cells with reduced Fbxo7 expression show increased glycolysis, despite lower cell viability and activation levels. Metabolomic studies of activated CD4+ T cells confirm increased glycolytic flux in Fbxo7-deficient cells, as well as altered nucleotide biosynthesis and arginine metabolism. We show Fbxo7 expression is glucose-responsive at the mRNA and protein level, and we propose Fbxo7 inhibits PFKP and glycolysis via its activation of Cdk6.","PeriodicalId":343306,"journal":{"name":"The Journal of Cell Biology","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130001937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Tyrosine phosphorylation of S1PR1 leads to chaperone BiP-mediated import to the endoplasmic reticulum. 酪氨酸磷酸化S1PR1导致伴侣蛋白bip介导的内质网输入。

IF 7.8

The Journal of Cell Biology Pub Date : 2021-11-01 Epub Date: 2021-10-15 DOI: 10.1083/jcb.202006021

Mumtaz Anwar, Md Ruhul Amin, Vijay Avin Balaji Ragunathrao, Jacob Matsche, Andrei Karginov, Richard D Minshall, Gary C H Mo, Yulia Komarova, Dolly Mehta

{"title":"Tyrosine phosphorylation of S1PR1 leads to chaperone BiP-mediated import to the endoplasmic reticulum.","authors":"Mumtaz Anwar, Md Ruhul Amin, Vijay Avin Balaji Ragunathrao, Jacob Matsche, Andrei Karginov, Richard D Minshall, Gary C H Mo, Yulia Komarova, Dolly Mehta","doi":"10.1083/jcb.202006021","DOIUrl":"https://doi.org/10.1083/jcb.202006021","url":null,"abstract":"Cell surface G protein-coupled receptors (GPCRs), upon agonist binding, undergo serine-threonine phosphorylation, leading to either receptor recycling or degradation. Here, we show a new fate of GPCRs, exemplified by ER retention of sphingosine-1-phosphate receptor 1 (S1PR1). We show that S1P phosphorylates S1PR1 on tyrosine residue Y143, which is associated with recruitment of activated BiP from the ER into the cytosol. BiP then interacts with endocytosed Y143-S1PR1 and delivers it into the ER. In contrast to WT-S1PR1, which is recycled and stabilizes the endothelial barrier, phosphomimicking S1PR1 (Y143D-S1PR1) is retained by BiP in the ER and increases cytosolic Ca2+ and disrupts barrier function. Intriguingly, a proinflammatory, but non-GPCR agonist, TNF-α, also triggered barrier-disruptive signaling by promoting S1PR1 phosphorylation on Y143 and its import into ER via BiP. BiP depletion restored Y143D-S1PR1 expression on the endothelial cell surface and rescued canonical receptor functions. Findings identify Y143-phosphorylated S1PR1 as a potential target for prevention of endothelial barrier breakdown under inflammatory conditions.","PeriodicalId":343306,"journal":{"name":"The Journal of Cell Biology","volume":" ","pages":""},"PeriodicalIF":7.8,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/9f/14/JCB_202006021.PMC8562845.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39520569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Repression of CENP-A assembly in metaphase requires HJURP phosphorylation and inhibition by M18BP1 中期抑制CENP-A组装需要HJURP磷酸化和M18BP1的抑制

The Journal of Cell Biology Pub Date : 2021-10-28 DOI: 10.1101/2021.10.28.466278

J. C. F. Servin, A. Straight

{"title":"Repression of CENP-A assembly in metaphase requires HJURP phosphorylation and inhibition by M18BP1","authors":"J. C. F. Servin, A. Straight","doi":"10.1101/2021.10.28.466278","DOIUrl":"https://doi.org/10.1101/2021.10.28.466278","url":null,"abstract":"Centromeres are the foundation for mitotic kinetochore assembly and thus are essential for chromosome segregation. Centromeres are epigenetically defined by nucleosomes containing the histone H3 variant CENP-A. CENP-A nucleosome assembly is uncoupled from replication and occurs in G1 but how cells control this timing is incompletely understood. The formation of CENP-A nucleosomes in vertebrates requires CENP-C and the Mis18 complex which recruit the CENP-A chaperone HJURP to centromeres. Using a cell-free system for centromere assembly in X. laevis egg extracts, we discover two activities that inhibit CENP-A assembly in metaphase. HJURP phosphorylation prevents the interaction between HJURP and CENP-C in metaphase, blocking the delivery of soluble CENP-A to centromeres. Non-phosphorylatable mutants of HJURP constitutively bind CENP-C in metaphase but are not sufficient for new CENP-A assembly. We find that the M18BP1.S subunit of the Mis18 complex also binds to CENP-C to competitively inhibit HJURP’s access to centromeres. Removal of these two inhibitory activities causes CENP-A assembly in metaphase. SUMMARY Vertebrate CENP-A assembly is normally restricted to G1 phase. Two inhibitory activities, phosphorylation of HJURP and competitive binding of M18BP1.S to CENP-C, block HJURP’s access to the metaphase centromere. Removal of these inhibitory activities causes CENP-A assembly in metaphase.","PeriodicalId":343306,"journal":{"name":"The Journal of Cell Biology","volume":"222 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130181876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0