Fig. 1.

CAS protein structure and interactions. a CAS proteins conserve a common structure marked by four discrete domains: SH3 domain, an unstructured substrate domain, a 4-helix bundle, and an evolutionarily conserved C-terminal domain. Crystal structures have been obtained for the SH3 domain (1wyx) of human BCAR1 and 4-helix bundle (1z23) of rat BCAR1 are shown. Secondary structure predictions for the C-terminal domain are also shown; pattern of α-helices has some features of a focal adhesion-targeting (FAT) domain, but is not exactly the same. Amino acid sequences correspond to those for human BCAR1, and vary slightly for other family members. b For a number of important CAS interacting proteins, exact domains of interaction have been mapped, and are shown. Proteins known to interact with the substrate domain specifically through SH2/phospho-tyrosine interactions are thus indicated. A poly-proline domain common to BCAR1 and EFS is shown (Pro). See text for details