Docking protein that plays a role in tyrosine kinase-based signaling related to cell adhesion and cell spreading. Regulates PTK2/FAK1 activity, focal adhesion integrity, and cell spreading. Interacts (via SH3 domain) with PTK2/FAK1 (via C-terminus). Experimental confirmation may be lacking for some isoforms. Expressed abundantly in lung and spleen. Also highly expressed in ovarian and leukemia cell lines. Phosphorylated on tyrosines by SRC. Belongs to the CAS family.