CD29

Integrin beta-1 also known as CD29 is a protein that in humans is encoded by the ITGB1 gene. CD29 is an integrin unit associated with very late antigen receptors. It is known to conjoin with alpha-3 subunit to create α3β1 complex that reacts to such molecules as netrin-1 and reelin. In cardiac muscle and skeletal muscle, the integrin beta-1D isoform is specifically expressed, and localizes to costameres, where it aids in the lateral force transmission from the Z-discs to the extracellular matrix. Abnormal levels of integrin beta-1D have been found in limb girdle muscular dystrophy and polyneuropathy.

Structure

Integrin beta-1 can exist as different isoforms via alternative splicing. Six alternatively spliced variants have been found for this gene which encode five proteins with alternate C-termini. Integrin receptors exist as heterodimers, and greater than 20 different integrin heterodimeric receptors have been described. All integrins, alpha and beta forms, have large extracellular and short intracellular domains. The cytoplasmic domain of integrin beta-1 binds to the actin cytoskeleton. Integrin beta-1 is the most abundant beta-integrin expressed and associates with at least 10 different integrin-alpha subunits.