β-Integrin de-phosphorylation by the Density-Enhanced Phosphatase DEP-1 attenuates EGFR signaling in C. elegans

Abstract

Density-Enhanced Phosphatase-1 (DEP-1) de-phosphorylates various growth factor receptors and adhesion proteins to regulate cell proliferation, adhesion and migration. Moreover, dep-1/scc1 mutations have been detected in various types of human cancers, indicating a broad tumor suppressor activity. During C. elegans development, DEP-1 mediates binary cell fate decisions by negatively regulating EGFR signaling. Using a substrate-trapping DEP-1 mutant in a proteomics approach, we have identified the C. elegans β-integrin subunit PAT-3 as a specific DEP-1 substrate. DEP-1 selectively de-phosphorylates tyrosine 792 in the membrane-proximal NPXY motif to promote integrin activation via talin recruitment. The non-phosphorylatable β-integrin mutant pat-3(Y792F) partially suppresses the hyperactive EGFR signaling phenotype caused by loss of dep-1 function. Thus, DEP-1 attenuates EGFR signaling in part by de-phosphorylating Y792 in the β-integrin cytoplasmic tail, besides the direct de-phosphorylation of the EGFR. Furthermore, in vivo FRAP analysis indicates that the αβ-integrin/talin complex attenuates EGFR signaling by restricting receptor mobility on the basolateral plasma membrane. We propose that DEP-1 regulates EGFR signaling via two parallel mechanisms, by direct receptor de-phosphorylation and by restricting receptor mobility through αβ-integrin activation.

Comprehensive Endogenous Tagging of Basement Membrane Components Reveals Dynamic Movement within the Matrix Scaffolding

“…Caenorhabitis elegans is a powerful model in which to examine BM biology. CRISPR-Cas9-mediated homologous recombination has facilitated the generation of endogenously tagged laminin, type IV collagen, nidogen, integrin, and dystroglycan genes with genetically encoded fluorophores (Jayadev et al, 2019;Matsuo et al, 2019;Naegeli et al, 2017;Walser et al, 2017). C. elegans is also small and translucent, which allows live imaging of BMs from the embryo through adulthood.…”

Altered Met receptor phosphorylation and LRP1-mediated uptake in cells lacking carbohydrate-dependent lysosomal targeting

“…The involvement of phosphatases may explain changes in cell surface abundance of other glycoproteins including cell adhesion molecules. For example, PTPRJ/Dep-1 and PTPRF have been shown to regulate integrin activation and recycling, respectively (52,53). Thus, a decrease in phosphatase activity could lead to altered surface residence of these proteins.…”

FLN‐1/filamin is required to anchor the actomyosin cytoskeleton and for global organization of sub‐cellular organelles in a contractile tissue

“…We found that in wild type animals, DEB-1 decorates the basal actin stress fibers, with some localization to cell junctions (Figure 5c We next asked if this redistribution of DEB-1/vinculin is accompanied by the redistribution of TLN-1/talin (Cram, Clark, & Schwarzbauer, 2003;Moulder, Huang, Waterston, & Barstead, 1996) and PAT-3/β-integrin (Gettner, Kenyon, & Reichardt, 1995). We knocked down fln-1 using RNAi in animals expressing endogenously tagged TLN-1 or PAT-3 (Walser, Umbricht, Fröhli, Nanni, & Hajnal, 2017), and stained for F-actin and nuclei using phalloidin and DAPI, respectively. (Figure 1b).…”