title: N-cadherin activation substitutes for the cell contact control in cell cycle arrest and myogenic differentiation: involvement of p120 and beta-catenin.
abstract: N-cadherin is expressed throughout skeletal myogenesis and has been proposed to be involved in the differentiation program of myogenic precursors. Here, we further characterize the N-cadherin involvement and its mechanism of action at the onset of differentiation, through controlled N-cadherin activation by plating isolated C2 myoblasts on surfaces coated with a chimeric Ncad-Fc homophilic ligand (N-cadherin ectodomain fused to the immunoglobulin G Fc fragment). We show that N-cadherin activation substitutes for the cell density in myogenic differentiation by promoting myogenin and troponin T expression. In addition, N-cadherin adhesion participates to the associated cell cycle arrest through the nuclear accumulation of cyclin-dependent kinase inhibitors p21 and p27. Mouse primary myoblast cultures exhibited similar responses to N-cadherin as C2 cells. RNA interference knockdowns of the N-cadherin-associated cytoplasmic proteins p120 and beta-catenin produced opposite effects on the differentiation pathway. p120 silencing resulted in a decreased myogenic differentiation, associated with a reduction in cadherin-catenin content, which may explain its action on myogenic differentiation. beta-Catenin silencing led to a stimulatory effect on myogenin expression, without any effect on cell cycle. Our results demonstrate that N-cadherin adhesion may account for cell-cell contact-dependent cell cycle arrest and differentiation of myogenic cells, involving regulation through p120 and beta-catenins.
authors.affiliation: Signalisation et Différenciation Cellulaires dans les Systèmes Nerveux et Musculaire, U440 INSERM/UPMC, Institut du Fer à Moulin, 17 rue du Fer à Moulin, 75005 Paris, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Gavard
authors.forename: Véronique
authors.initials: V
authors.lastname: Marthiens
authors.forename: Céline
authors.initials: C
authors.lastname: Monnet
authors.forename: Mireille
authors.initials: M
authors.lastname: Lambert
authors.forename: René Marc
authors.initials: RM
authors.lastname: Mège
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001973:Bromodeoxyuridine / Q000494:pharmacology; D015820:Cadherins / Q000737:chemistry / Q000378:metabolism*; D002448:Cell Adhesion; D002450:Cell Communication; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism; D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D019070:Cell Lineage; D002478:Cells, Cultured; D050760:Cyclin-Dependent Kinase Inhibitor p27; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D020868:Gene Silencing; D007128:Immunoglobulin Fragments / Q000737:chemistry; D007074:Immunoglobulin G / Q000737:chemistry; D008024:Ligands; D051379:Mice; D032342:Muscle Cells / Q000378:metabolism*; D011485:Protein Binding; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism*; D014162:Transfection; D020107:Troponin T / Q000737:chemistry; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D051176:beta Catenin; D020729:p120 GTPase Activating Protein / Q000378:metabolism*
chemical_list: C495267:CTNNB1 protein, mouse; D015820:Cadherins; C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D007128:Immunoglobulin Fragments; D007074:Immunoglobulin G; D008024:Ligands; D034741:RNA, Small Interfering; D015534:Trans-Activators; D020107:Troponin T; D025521:Tumor Suppressor Proteins; D051176:beta Catenin; D020729:p120 GTPase Activating Protein; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004247:DNA; D001973:Bromodeoxyuridine