{"title":"A size filter at the Golgi regulates apical membrane protein sorting","authors":"Christian de Caestecker, Ian G. Macara","doi":"10.1038/s41556-024-01500-0","DOIUrl":null,"url":null,"abstract":"Despite decades of research, apical sorting of epithelial membrane proteins remains incompletely understood. We noted that apical cytoplasmic domains are smaller than those of basolateral proteins; however, the reason for this discrepancy is unknown. Here we used a synthetic biology approach to investigate whether a size barrier at the Golgi apparatus might hinder apical sorting of proteins with large cytoplasmic tails. We focused on Crb3, Ace2 and Muc1 as representative apical proteins with short cytoplasmic tails. By incorporating a streptavidin-binding peptide, these proteins can be trapped in the endoplasmic reticulum until addition of biotin, which triggers synchronous release to the Golgi and subsequent transport to the apical cortex. Strikingly, increasing the size of their cytoplasmic domains caused partial mislocalization to the basolateral cortex and significantly delayed Golgi departure. Moreover, N-glycosylation of ‘large’ Crb3 was delayed, and ‘small’ Crb3 segregated into spatially distinct Golgi regions. Biologically, Crb3 forms a complex through its cytoplasmic tail with the Pals1 protein, which could also delay departure, but although associated at the endoplasmic reticulum and Golgi, Pals1 disassociated before Crb3 departure. Notably, a non-dissociable mutant Pals1 hampered the exit of Crb3. We conclude that, unexpectedly, a size filter at the Golgi facilitates apical sorting of proteins with small cytoplasmic domains and that timely release of Pals1, to reduce cytoplasmic domain size, is essential for normal Crb3 sorting. de Caestecker and Macara study apical sorting of proteins with varying cytoplasmic tail length in epithelial cells. They propose that a size filter at the Golgi facilitates apical sorting of proteins with small cytoplasmic domains.","PeriodicalId":18977,"journal":{"name":"Nature Cell Biology","volume":"26 10","pages":"1678-1690"},"PeriodicalIF":17.3000,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nature Cell Biology","FirstCategoryId":"99","ListUrlMain":"https://www.nature.com/articles/s41556-024-01500-0","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CELL BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Despite decades of research, apical sorting of epithelial membrane proteins remains incompletely understood. We noted that apical cytoplasmic domains are smaller than those of basolateral proteins; however, the reason for this discrepancy is unknown. Here we used a synthetic biology approach to investigate whether a size barrier at the Golgi apparatus might hinder apical sorting of proteins with large cytoplasmic tails. We focused on Crb3, Ace2 and Muc1 as representative apical proteins with short cytoplasmic tails. By incorporating a streptavidin-binding peptide, these proteins can be trapped in the endoplasmic reticulum until addition of biotin, which triggers synchronous release to the Golgi and subsequent transport to the apical cortex. Strikingly, increasing the size of their cytoplasmic domains caused partial mislocalization to the basolateral cortex and significantly delayed Golgi departure. Moreover, N-glycosylation of ‘large’ Crb3 was delayed, and ‘small’ Crb3 segregated into spatially distinct Golgi regions. Biologically, Crb3 forms a complex through its cytoplasmic tail with the Pals1 protein, which could also delay departure, but although associated at the endoplasmic reticulum and Golgi, Pals1 disassociated before Crb3 departure. Notably, a non-dissociable mutant Pals1 hampered the exit of Crb3. We conclude that, unexpectedly, a size filter at the Golgi facilitates apical sorting of proteins with small cytoplasmic domains and that timely release of Pals1, to reduce cytoplasmic domain size, is essential for normal Crb3 sorting. de Caestecker and Macara study apical sorting of proteins with varying cytoplasmic tail length in epithelial cells. They propose that a size filter at the Golgi facilitates apical sorting of proteins with small cytoplasmic domains.
期刊介绍:
Nature Cell Biology, a prestigious journal, upholds a commitment to publishing papers of the highest quality across all areas of cell biology, with a particular focus on elucidating mechanisms underlying fundamental cell biological processes. The journal's broad scope encompasses various areas of interest, including but not limited to:
-Autophagy
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-Cell cycle and growth
-Cell death
-Chromatin and epigenetics
-Cytoskeletal dynamics
-Developmental biology
-DNA replication and repair
-Mechanisms of human disease
-Mechanobiology
-Membrane traffic and dynamics
-Metabolism
-Nuclear organization and dynamics
-Organelle biology
-Proteolysis and quality control
-RNA biology
-Signal transduction
-Stem cell biology