Splice variants of human beta 1 integrins: origin, biosynthesis and functions.

The integrin beta1 subfamily of adhesion receptors consists of 12 members and forms the biggest subfamily among integrins. Human integrin subunit beta1 has five cytoplasmic splice variants (beta1A, beta1B, beta1C-1, beta1-C2, beta1D). Even though cytoplasmic splice variants do not change the ligand-specificity of a beta1 integrin, clustering of these different splice variants triggers signaling pathways that lead to a different cellular response. The main focus of this review is on the origin and specific functions of the less abundant human integrin beta1 splice variants (B, C-1, C-2, D).