C. elegans Vulva Induction: An In Vivo Model to Study Epidermal Growth Factor Receptor Signaling and Trafficking

2021

Development

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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. To understand how the LIN-2/7/10 complex regulates receptor localization, we determined its expression and localization during vulva development. We found that LIN-7 colocalizes with LET-23 EGFR at the basolateral membrane, whereas the LIN-2/7/10 complex colocalizes with LET-23 EGFR at cytoplasmic punctae, that mostly overlap with the Golgi. Furthermore, 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 consistent with their forming a subcomplex. Thus, the LIN-2/7/10 complex forms on the Golgi where it likely targets LET-23 EGFR trafficking to the basolateral membrane rather than functioning as a tether.

Section: Microscopy and Image Analysismentioning

confidence: 99%

Golgi localization of the LIN-2/7/10 complex points to a role in basolateral secretion of LET-23 EGFR in the Caenorhabditis elegans vulval precursor cells

2021

Development

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“…Wild-type worms have a VPC induction score of 3 because only three of six VPCs (P5.p–P7.p) are induced. Worms were classified as Vul if they had a VPC induction score of less than 3, or multivulva (Muv) if they had an induction score of greater than 3 ( Gauthier and Rocheleau, 2017 ). Worms with detectable fluorescence signal in their vulval cells (driven by the lin-31 promoter) and in neurons in their head (driven by the ttx-3 promoter of the coinjection marker) were compared with siblings taken from the same plate with no fluorescence signal in both their vulval cells and neurons as negative controls.…”

Section: Methodsmentioning

confidence: 99%

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

2021

MBoC

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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; 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. 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.

“…Wild type worms have a VPC induction score of 3 because only 3 of 6 VPCs (P5.p-P7.p) are induced. Worms were classified as Vul if they had a VPC induction score of less than 3, or multivulva (Muv) if they had an induction score of greater than 3 (Gauthier and Rocheleau, 2017). Worms with detectable fluorescent signal in their vulval cells (driven by the lin-31 promoter) and in neurons in their head (driven by the ttx-3 promoter of the co-expression marker) were compared to siblings taken from the same plate with no fluorescent signal in both their vulval cells and neurons as negative controls.…”

Section: Vulval Cell Fate Induction Scoringmentioning

confidence: 99%

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

2020

Preprint

Self Cite

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.