Rho GTPases and lipid signaling

Our laboratory is interested in the study of the signaling pathways and biological responses mediated by the lipid second messengers through the Rho GTPases. The activation of RhoGTPases is controlled by three groups of proteins: GEFs (guanosine exchange factors), GAPs (GTPase activating proteins) and GDIs (guanosine dissociation inhibitors). In our group we are studying a family of GAP proteins, the chimaerins. These proteins have a unique structure with a C1 domain that binds diacylglycerol (DAG) and phorbol esters, a GAP domain that specifically inactivates RhoGTPase Rac, and an SH2 domain present only in some isoforms. These characteristics allow chimaerins to connect the signaling by DAG with the activation of Rac. Our current objective is to analyze the regulation of Rac mediated by chimaerins and determine their role in cell biology and physiopathology.