DOCK180 family proteins are Rho guanine nucleotide exchange factors. DOCK1-5 contains an N-terminal SH3 domain implicated in their autoinhibition. Release of the closed conformation requires the interaction between SH3 and engulfment and cell motility (ELMO). Here, we solved the solution structure of DOCK180 SH3 domain, which shares similar target binding features with the SH3 domain of DOCK2. The conserved N-terminal extension packs with the SH3 core domain and forms a new target binding site distinct from the canonical "PxxP" site. Our results demonstrate that the bidentate target binding mode of DOCK180 SH3 domain might be a general feature in all DOCK proteins.
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