Cib2 binds integrin a7Bb1D and is reduced in laminin a2 chain deficient muscular dystrophy
Author
Summary, in English
Mutations in the gene encoding laminin alpha 2 chain cause congenital muscular dystrophy type 1A. In skeletal muscle, laminin alpha 2 chain binds at least two receptor complexes: the dystrophin-glycoprotein complex and integrin alpha 7 beta 1. To gain insight into the molecular mechanisms underlying this disorder, we performed gene expression profiling of laminin alpha 2 chain-deficient mouse limb muscle. One of the down-regulated genes encodes a protein called Cib2 (calcium-and integrin-binding protein 2) whose expression and function is unknown. However, the closely related Cib1 has been reported to bind integrin alpha IIb and may be involved in outside-in-signaling in platelets. Since Cib2 might be a novel integrin alpha 7 beta 1-binding protein in muscle, we have studied Cib2 expression in the developing and adult mouse. Cib2 mRNA is mainly expressed in the developing central nervous system and in developing and adult skeletal muscle. In skeletal muscle, Cib2 colocalizes with the integrin alpha 7B subunit at the sarcolemma and at the neuromuscular and myotendinous junctions. Finally, we demonstrate that Cib2 is a calcium-binding protein that interacts with integrin alpha 7B beta 1D. Thus, our data suggest a role for Cib2 as a cytoplasmic effector of integrin alpha 7B beta 1D signaling in skeletal muscle.
Publishing year
2008
Language
English
Pages
24760-24769
Publication/Series
Journal of Biological Chemistry
Volume
283
Issue
36
Document type
Journal article
Publisher
American Society for Biochemistry and Molecular Biology
Topic
- Cell and Molecular Biology
Status
Published
Research group
- Muscle Biology
ISBN/ISSN/Other
- ISSN: 1083-351X