Non-centrosomal epidermal microtubules act in parallel to LET-502/ROCK to promote C. elegans elongation.
Fiche publication
Date publication
novembre 2015
Auteurs
Membres identifiés du Cancéropôle Est :
Dr GALLY Christelle, Dr HYENNE Vincent
Tous les auteurs :
Quintin S, Wang S, Pontabry J, Bender A, Robin F, Hyenne V, Landmann F, Gally C, Oegema K, Labouesse M
Lien Pubmed
Résumé
C. elegans embryonic elongation is a morphogenetic event driven by actomyosin contractility and muscle-induced tension transmitted through hemidesmosomes. A role for the microtubule cytoskeleton has also been proposed, but its contribution remains poorly characterized. Here, we investigate the organization of the non-centrosomal microtubule arrays present in the epidermis and assess their function in elongation. We show that the microtubule regulators gamma-tubulin and NOCA-1 are recruited to hemidesmosomes and adherens junctions early in elongation. Several parallel approaches suggest that microtubule nucleation occurs from these sites. Disrupting the epidermal microtubule array by overexpressing the microtubule-severing protein Spastin or by inhibiting the C. elegans ninein homolog NOCA-1 in the epidermis mildly affected elongation. However, microtubules were essential for elongation when hemidesmosomes or the activity of the Rho-kinase LET-502/ROCK were partially compromised. Imaging of junctional components and genetic analyses suggest that epidermal microtubules function together with Rho-kinase to promote the transport of E-cadherin to adherens junctions and myotactin to hemidesmosomes. Our results indicate that LET-502/ROCK role in junctional remodeling is likely independent of its established function as a myosin II activator, but requires a microtubule-dependent pathway involving the syntaxin SYX-5. Hence, we propose that non-centrosomal microtubules organized by epidermal junctions contribute to elongation by transporting junction remodeling factors, rather than having a mechanical role.
Référence
Development. 2015 Nov 19. pii: dev.126615.