Meisosomes, folded membrane platforms, link the epidermis to the cuticle in C. elegans

• Published in: bioRxiv
• Main Authors: Aggad, Dina, Brouilly, Nicolas, Omi, Shizue, Essmann, Clara L, Dehapiot, Benoit, Savage-Dunn, Cathy, Fabrice, Richard, Cazevieille, Chantal, Politi, Kristin A, Hall, David D, Pujol, Remy, Pujol, Nathalie
• Format: Paper
• Language: English
• Published: Cold Spring Harbor Cold Spring Harbor Laboratory Press 25.01.2023
• Subjects: Caenorhabditis elegans; Collagen; Cytoskeleton; Epicuticle; Mechanical properties; Molting; Mutants
• DOI: 10.1101/2021.11.26.470028

Apical extracellular matrices (aECMs) form a physical barrier to the environment. In C. elegans, the epidermal aECM, the cuticle, is composed mainly of different types of collagen, associated in circumferential ridges separated by furrows. Here, we show that in mutants lacking furrows, the normal intimate connection between the epidermis and the cuticle is lost, specifically at the lateral epidermis, where, in contrast to the dorsal and ventral epidermis, there are no hemidesmosomes. At the ultrastructural level, there is a profound alteration of structures that we term meisosomes, in reference to eisosomes in yeast. We show that meisosomes are composed of stacked parallel folds of the epidermal plasma membrane, alternately filled with cuticle. We propose that just as hemidesmosomes connect the dorsal and ventral epidermis, above the muscles, to the cuticle, meisosomes connect the lateral epidermis to it. Moreover, furrow mutants present marked modifications of the biomechanical properties of their skin and exhibit a constitutive damage response in the epidermis. As meisosomes co-localise to macrodomains enriched in phosphatidylinositol (4,5) bisphosphate, they might act, like eisosomes, as signalling platforms, to relay tensile information from the aECM to the underlying epidermis, as part of an integrated stress response to damage.Competing Interest StatementThe authors have declared no competing interest.Footnotes* - reorganisation of the results - VHA-5 can serve as a "bona fide" meisosome marker (KI, CLEM) - ultrastructural caracterisation - complementation with hemidesmosome - co-localise to macrodomains enriched in phosphatidylinositol (4,5) bisphosphate - fragmentation in furrow dpy - detachment of cuticle and cytoplasmic extrusions