Integrin-linked kinase is a positive mediator of L6 myoblast differentiation

Mathew G Miller, Izabela Naruszewicz, Ashu S Kumar, Toolsie Ramlal, Gregory E Hannigan

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22 Citations (Scopus)

Abstract

Overexpression of ILK in L6 myoblasts results in increased ILK kinase activity, stimulating myotube formation and induction of biochemical differentiation markers. Expression of a dominant negative ILK mutant, ILK(E359K), inhibits endogenous ILK activation and L6 differentiation. Cell cycle analysis of ILK(E359K) cells cultured in serum-free conditions indicates significant apoptosis (11-19 sub-diploid peak) which is not seen in insulin treated cells. Expression of ILK variants does not have significant effects on S-phase transit, however. Known targets of ILK, PKB/Akt or glycogen synthase kinase 3beta are not obviously involved in ILK-induced L6 differentiation. Insulin-stimulated phosphorylation of PKB at Ser473 is unimpaired in the ILK(E359K) cells, suggesting that PKB is not a myogenic target of ILK. Inhibition of GSK3beta by LiCl blocks L6 myogenesis, indicating that ILK-mediated inhibition of GSK3beta is not sufficient for differentiation. Our data do suggest that a LiCl-sensitive interaction of ILK is important in L6 myoblast differentiation.
Original languageEnglish
Pages (from-to)796 - 803
Number of pages8
JournalBiochemical and Biophysical Research Communications
Volume310
Issue number3
DOIs
Publication statusPublished - 2003
Externally publishedYes

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