Seems to act as an adapter protein between membrane proteins and the actin cytoskeleton (By similarity). In collaboration with CBLC, modulates the rate of RET turnover and may act as regulatory checkpoint that limits the potency of GDNF on neuronal survival. Controls CBLC function, converting it from an inhibitor to a promoter of RET degradation (By similarity). May play a role in receptor clustering and cytoskeletal polarity in the junction between T-cell and antigen-presenting cell (PubMed:9741631). May anchor the podocyte slit diaphragm to the actin cytoskeleton in renal glomerolus (PubMed:10514378). Also required for cytokinesis. Plays a role in epithelial cell junctions formation (By similarity). Homodimer. Interacts with F-actin, PKD2, NPHS1 and NPHS2. Interacts with WTIP. Interacts with DDN; interaction is direct. Interacts (via SH3 2 domain) with CBL (via phosphorylated C-terminus). Interacts with BCAR1/p130Cas (via SH3 domain). Interacts with MVB12A and ARHGAP17. Interacts with ANLN, CD2 and CBLB. Interacts with PDCD6IP and TSG101. Interacts with RIN3. Interacts directly with RET (inactive) and CBLC; upon RET activation by GDNF suggested to dissociate from RET as CBLC:CD2AP complex. Interacts with CGNL1 and SH3BP1; probably part of a complex at cell junctions. Interacts with CAPZA1. Colocalizes with F-actin and BCAR1/p130Cas in membrane ruffles (By similarity). Located at podocyte slit diaphragm between podocyte foot processes (PubMed:10514378, PubMed:11733379). During late anaphase and telophase, concentrates in the vicinity of the midzone microtubules and in the midbody in late telophase (By similarity). Expressed in podocytes (at protein level). Potential homodimerization is mediated by the coiled coil domain. Phosphorylated on tyrosine residues; probably by c-Abl, Fyn and c-Src. Death at 6 to 7 weeks of age from renal failure. Mice show defects in epithelial foot processes, accompanied by mesangial cell hyperplasia and extracellular matrix deposition.