Cadherin complexity: recent insights into cadherin superfamily function in C. elegans

Abstract

Cadherin superfamily proteins mediate cell-cell adhesion during development. The C. elegans embryo is a powerful system for analyzing how cadherins function in highly stereotyped morphogenetic events. In the embryo, the classical cadherin HMR-1 acts along with the Rac pathway and SAX-7/L1CAM during gastrulation. As adherens junctions mature, PAR complex proteins differentially regulate cadherin complex localization, and SRGP-1/Slit/Robo GAP aids adhesion by promoting membrane bending. Once adherens junctions form, actin is linked to the cell surface via HMP-1/α-catenin, whose actin binding activity is regulated in novel ways. FMI-1/Flamingo and CDH-4/Fat-like regulate axonal morphology of both pioneer and follower neurons. C. elegans thus continues to be useful for uncovering precise functions for cadherin superfamily proteins and their associates in a simple metazoan.

The fat-like cadherin CDH-4 acts cell-non-autonomously in anterior–posterior neuroblast migration

“…Fat-like cadherins have been implicated in acting in parallel to Wnt signaling in planar cell polarity, (Cho and Irvine, 2004; Loveless and Hardin, 2012; Matakatsu and Blair, 2004; Rawls et al, 2002; Strutt and Strutt, 2002; Tanoue and Takeichi, 2004; Yang et al, 2002). EGL-20/Wnt, which controls Q descendant migrations including PQR to the posterior, showed no early Q migration defects (Chapman et al, 2008).…”

“…In C. elegans , CDH-4 has been implicated in axon development and cell migration, including migration of Q cell descendants (Najarro et al, 2012; Schmitz et al, 2008). In Drosophila , Fat is thought to coordinate cellular asymmetry generated by the core planar cell polarity pathway components with tissue and organismal polarity in a non-autonomous fashion, and to be distributed asymmetrically across imaginal disc primordia in response to Wnt signaling (Cho and Irvine, 2004; Loveless and Hardin, 2012; Ma et al, 2003; Matakatsu and Blair, 2004; Rawls et al, 2002; Strutt and Strutt, 2002; Tanoue and Takeichi, 2004; Thomas and Strutt, 2012; Yang et al, 2002). …”

A WAVE2–Arp2/3 actin nucleator apparatus supports junctional tension at the epithelial zonula adherens

“…, 2012). Junctional tension in the ZA may contribute to morphogenesis of epithelial sheets (Loveless and Hardin, 2012), orient cells within tissues (Fernandez-Gonzalez et al. , 2009), and allow the ZA to resist side-to-side (orthogonal) forces (Smutny et al.…”

Getting to the core of cadherin complex function in Caenorhabditis elegans

“…Previous work on the PAR complex similarly showed differential requirements in different tissues. While PAR-3 is critical for CCC establishment in the intestine, it is surprisingly dispensable in the epidermis, although localization of HMR-1 and DLG-1 is eventually lost, along with the mechanical integrity of the epidermis ( 36 ; reviewed in 62 ). What might account for such differences?…”