Functional cross-talk between ras and rho pathways: a Ras-specific GTPase-activating protein (p120RasGAP) competitively inhibits the RhoGAP activity of deleted in liver cancer (DLC) tumor suppressor by masking the catalytic arginine finger.

The three deleted in liver cancer genes (DLC1-3) encode Rho-specific GTPase-activating proteins (RhoGAPs). Their expression is frequently silenced in a variety of cancers. The RhoGAP activity, which is required for full DLC-dependent tumor suppressor activity, can be inhibited by the Src homology 3 (SH3) domain of a Ras-specific GAP (p120RasGAP).

SH3-mediated targeting of Wrch1/RhoU by multiple adaptor proteins.

Wrch1/RhoU is an atypical member of the Rho family. A major structural difference is the extended N-terminus of Wrch1 (nWrch1) containing three putative SH3 domain-binding motifs whose specificities are unknown. To define the impact of this extended region on coupling Wrch1 to cellular signaling, we analyzed in this study nWrch1 interaction with Src homology 3 (SH3) domains of different adaptor proteins.