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A polarity pathway for exocyst-dependent intracellular tube extension.

ABSTRACT: Lumen extension in intracellular tubes can occur when vesicles fuse with an invading apical membrane. Within the Caenorhabditis elegans excretory cell, which forms an intracellular tube, the exocyst vesicle-tethering complex is enriched at the lumenal membrane and is required for its outgrowth, suggesting that exocyst-targeted vesicles extend the lumen. Here, we identify a pathway that promotes intracellular tube extension by enriching the exocyst at the lumenal membrane. We show that PAR-6 and PKC-3/aPKC concentrate at the lumenal membrane and promote lumen extension. Using acute protein depletion, we find that PAR-6 is required for exocyst membrane recruitment, whereas PAR-3, which can recruit the exocyst in mammals, appears dispensable for exocyst localization and lumen extension. Finally, we show that CDC-42 and RhoGEF EXC-5/FGD regulate lumen extension by recruiting PAR-6 and PKC-3 to the lumenal membrane. Our findings reveal a pathway that connects CDC-42, PAR proteins, and the exocyst to extend intracellular tubes.

SUBMITTER: Abrams J

PROVIDER: S-EPMC8021397 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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A polarity pathway for exocyst-dependent intracellular tube extension.

Abrams Joshua J Nance Jeremy J

eLife 20210309

Lumen extension in intracellular tubes can occur when vesicles fuse with an invading apical membrane. Within the <i>Caenorhabditis elegans</i> excretory cell, which forms an intracellular tube, the exocyst vesicle-tethering complex is enriched at the lumenal membrane and is required for its outgrowth, suggesting that exocyst-targeted vesicles extend the lumen. Here, we identify a pathway that promotes intracellular tube extension by enriching the exocyst at the lumenal membrane. We show that PAR ...[more]

PMID: 33687331

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