Interaction of two proline-rich sequences of cell adhesion kinase β with SH 3 domains of p 130 Cas-related proteins and a GTPase-activating protein ,

Cell adhesion kinase β (CAKβ ) is a protein tyrosine kinase closely related to focal adhesion kinase (FAK) in structure. CAKβ contains two proline-rich sequences within its C-terminal region. Since proline-rich sequences present in the corresponding region of FAK are known to mediate protein–protein interactions by binding to SH3 domains, we investigated binding of CAKβ to a panel of SH3 domains. Affinity precipitation from rat brain lysate revealed selective interactions of CAKβ with glutathione S-transferase (GST)-fused SH3 domains of p130Cas(Cas)related proteins and Graf. Mutational analysis indicated that the proline-rich sequences of CAKβ mediate this interaction. Each