Kindlin-2 is required for myocyte elongation and is essential for myogenesis

James J Dowling¹ , Andrew P Vreede² , Susie Kim² , Jeffrey Golden³ and Eva L Feldman²

¹Department of Pediatrics, University of Michigan, Ann Arbor, USA

²Department of Neurology, University of Michigan, Ann Arbor, USA

³Department of Neuropathology, Children's Hospital of Philadelphia, Philadelphia, USA

author email corresponding author email

BMC Cell Biology 2008, 9:36doi:10.1186/1471-2121-9-36


Published:	8 July 2008

Abstract

Background

Integrins are required for normal muscle differentiation and disruptions in integrin signaling result in human muscle disease. The intracellular components that regulate integrin function during myogenesis are poorly understood. Unc-112 is an integrin-associated protein required for muscle development in C. elegans. To better understand the intracellular effectors of integrin signaling in muscle, we examined the mammalian homolog of Unc-112, kindlin-2.

Results

Kindlin-2 expression is upregulated during differentiation and highly enriched at sites of integrin localization. RNAi knockdown of kindlin-2 in C2C12 cells results in significant abnormalities during the early stages of myogenesis. Specifically, differentiating myocytes lacking kindlin-2 are unable to elongate and fail to fuse into multinucleated myotubes. These changes are correlated with decreased cell substratum adhesion and increased cell motility. They are also associated with redistribution of a known kindlin-2 binding partner, integrin linked kinase (ILK), to the membrane insoluble subcellular fraction.

Conclusion

In all, our study reveals kindlin-2 as a novel integrin adaptor protein important for muscle differentiation, and identifies it particularly as a critical regulator of myocyte elongation.