Docking protein which plays a central coordinating role for tyrosine-kinase-based signaling related to cell adhesion. May serve as an activator of SRC and a downstream effector. Interacts with the SH3 domain of FYN and with CRK, SRC, and YES (By similarity). The protein has been detected in lung and placenta. Contains a central domain (substrate domain) containing multiple potential SH2-binding sites and a C-terminal domain containing a divergent helix-loop-helix (HLH) motif. The SH2-binding sites putatively bind CRK, NCK and ABL SH2 domains. The SH3-binding sites that bind to the SRC SH3 domain are required for interaction with CRK and are implicated in promotion of serum response element (SRE) activation. The SH3 domain interacts with PTK2/FAK1. Phosphorylated on multiple tyrosine residues. Phosphorylated on tyrosines by FYN and SRC (By similarity). Belongs to the CAS family.