Biology subjects

Rocheleau, C. E.

Publications and source records attributed to Rocheleau, C. E..

3 recordsLinked to original sources

bioRxiv2021

The Rab GTPase activating protein TBC-2 extends longevity by facilitating release of FOXO/DAF-16 from endosomes

FOXO transcription factors have been shown to regulate longevity in model organisms and are associated with longevity in humans. To gain insight into how FOXO functions to increase lifespan, we examined the subcellular localization of DAF-16 in C. elegans. We show that DAF-16 is localized to endosomes and that this endosomal localization is increased by the insulin-IGF signaling (IIS) pathway. Endosomal localization of DAF-16 is modulated by endosomal trafficking proteins. Disruption of the Rab GTPase activating protein TBC-2 increases endosomal localization of DAF-16, while inhibition of TBC-2 targets, RAB-5 or RAB-7 GTPases, decreases endosomal localization of DAF-16. Importantly, the amount of DAF-16 that is localized to endosomes has functional consequences as increasing endosomal localization through mutations in tbc-2 reduced the lifespan of long-lived daf-2 IGFR mutants, depleted their fat stores, and DAF-16 target gene expression. Overall, this work identifies endosomal localization as a mechanism regulating DAF-16 FOXO, which is important for its functions in metabolism and aging.

cell biology↗

bioRxiv2020

LIN-10 can promote LET-23 EGFR signaling and trafficking independently of LIN-2 and LIN-7

During C. elegans larval development, an inductive signal mediated by LET-23 EGFR (Epidermal Growth Factor Receptor) specifies three of six vulva precursor cells (VPCs) to adopt vulval cell fates. An evolutionarily conserved complex consisting of PDZ domain-containing scaffold proteins LIN-2 (CASK), LIN-7 (Lin7 or Veli), and LIN-10 (APBA1 or Mint1) (LIN-2/7/10) mediates basolateral LET-23 EGFR localization in the VPCs to permit signal transmission and development of the vulva. We recently found that the LIN-2/7/10 complex likely forms at Golgi ministacks or recycling endosomes; however, the mechanism through which the complex targets the receptor to the basolateral membrane remains unknown. Here we found that overexpression of LIN-10 or LIN-7 can compensate for loss of their complex components by promoting LET-23 EGFR signaling through previously unknown complex-independent and receptor-dependent pathways. In particular, LIN-10 can independently promote basolateral LET-23 EGFR localization, and its complex-independent function uniquely requires its PDZ domains that also regulate its localization to Golgi ministacks and recycling endosomes. These studies point to a novel complex-independent function for LIN-7 and LIN-10 that broadens our understanding of how this complex regulates targeted sorting of membrane proteins.

cell biology↗

bioRxiv2020

Dynamic expression and localization of the LIN-2/7/10 protein scaffolding complex during C. elegans vulval development

The evolutionarily conserved LIN-2 (CASK)/LIN-7 (Lin7A-C)/LIN-10 (APBA1) complex plays an important role in regulating spatial organization of membrane proteins and signaling components. In C. elegans, the complex is essential for development of the vulva by promoting the localization of the sole Epidermal Growth Factor Receptor (EGFR) orthologue, LET-23, to the basolateral membrane of the vulva precursor cells (VPCs) where it can specify the vulval cell fate. However, the expression and localization of the LIN-2/7/10 complex, and how the complex regulates receptor localization, are not known. Here we describe an in vivo analysis of the complex in C. elegans VPCs. Only LIN-7 colocalizes with LET-23 EGFR at the basolateral membrane, while the LIN-2/7/10 complex components instead colocalize at cytoplasmic foci, consistent with Golgi or endosomes. LIN-10 recruits LIN-2, which in turn recruits LIN-7. We demonstrate that the complex forms in vivo with particularly strong interaction and colocalization between LIN-2 and LIN-7. Our data suggest that the LIN-2/7/10 complex forms on endomembrane compartments where it likely targets LET-23 EGFR to the basolateral membrane, and point to distinct regulation between LIN-2/7 and LIN-10. Summary StatementLIN-10 recruits LIN-2 and LIN-7 to Golgi or recycling endosomes, consistent with targeting rather than tethering the epidermal growth factor receptor to the basolateral membrane in C. elegans.

cell biology↗