(A). Schematic structures of DOCK proteins. The SH3 domain, Docker Homology Region 1/CDM-Zizimin Homology1, Docker Homology Region 2/CDM Zizimin Homology 2, and Proline-rich sequences (shown in red) are indicated. The circular structure indicates the putative location of the Crk binding sites. Note that in DOCK5, Crk has been shown to bind to a non-canonical proline sequence. In DOCK2, Crk has been proposed to bind independent of proline. (B). Structure of the autoinhibited DOCK1/Crk complex. See text for details.