Neuronal immunoglobulin superfamily cell adhesion molecules in epithelial morphogenesis: insights fromDrosophila

Abstract

In this review, we address the function of immunoglobulin superfamily cell adhesion molecules (IgCAMs) in epithelia. Work in the Drosophila model system in particular has revealed novel roles for calcium-independent adhesion molecules in the morphogenesis of epithelial tissues. We review the molecular composition of lateral junctions with a focus on their IgCAM components and reconsider the functional roles of epithelial lateral junctions. The epithelial IgCAMs discussed in this review have well-defined roles in the nervous system, particularly in the process of axon guidance, suggesting functional overlap and conservation in mechanism between that process and epithelial remodelling. We expand on the hypothesis that epithelial occluding junctions and synaptic junctions are compositionally equivalent and present a novel hypothesis that the mechanism of epithelial cell (re)integration and synaptic junction formation are shared. We highlight the importance of considering non-cadherin-based adhesion in our understanding of the mechanics of epithelial tissues and raise questions to direct future work. This article is part of the discussion meeting issue ‘Contemporary morphogenesis’.

A Drosophila RNAi screen reveals conserved glioblastoma-related adhesion genes that regulate collective cell migration

“…Lac (human LSAMP and NEGR1) is a membrane-localized protein with three extracellular immunoglobulin-like (Ig-like) domains that can mediate cell–cell adhesion ( Finegan and Bergstralh 2020 ). Lac localizes to both immature and mature basolateral septate junctions and is required for tracheal morphogenesis in Drosophila ( Llimargas et al 2004 ).…”

“…Rst (human KIRREL1, KIRREL2, and KIRREL3) is a member of the Irre Cell Recognition Module (IRM) family of transmembrane proteins. In particular, Rst encodes an immunoglobulin superfamily cell adhesion molecule (IgCAM) with five Ig-like domains ( Finegan and Bergstralh 2020 ). IRM proteins, including Rst, control the adhesion and patterning of various tissues including the developing ommatidia in the Drosophila eye ( Bao and Cagan 2005 ; Johnson et al 2011 ; Finegan and Bergstralh 2020 ).…”

ADrosophilaRNAi screen reveals conserved glioblastoma-related adhesion genes that regulate collective cell migration

“…Rst (human KIRREL1, KIRREL2, KIRREL3) is a member of the Irre Cell Recognition Module (IRM) family of transmembrane proteins. In particular, Rst encodes an immunoglobulin superfamily cell adhesion molecule (IgCAM) with five Ig-like domains (Finegan and Bergstralh 2020). IRM proteins, including Rst, control the adhesion and patterning of various tissues including the developing ommatidia in the Drosophila eye (Bao and Cagan 2005; Johnson et al 2011; Finegan and Bergstralh 2020).…”

“…In particular, Rst encodes an immunoglobulin superfamily cell adhesion molecule (IgCAM) with five Ig-like domains (Finegan and Bergstralh 2020). IRM proteins, including Rst, control the adhesion and patterning of various tissues including the developing ommatidia in the Drosophila eye (Bao and Cagan 2005; Johnson et al 2011; Finegan and Bergstralh 2020). Border cells expressing rst RNAi showed consistent though mild migration defects with three RNAi lines (VDRC 27223, VDRC 27225, and BL 28672), which in total target two non-overlapping regions of the rst gene.…”

Contemporary morphogenesis

“…Expanding on the tight links between cell shape and behaviour and tissue morphogenesis during development, we feature review articles into the roles of cytoskeleton-mediated forces [13], junction formation [14] and cell intercalation [15]. The extracellular matrix is a highly specialized mediator of multiple developmental processes, signalling to cells through modulating tissue stiffness or mediating bioavailability of secreted signalling molecules.…”