Unraveling a model of TCL/RhoJ allosterism using TC10 reverse chimeras.

In addition to the classical regulation of GTPase activity by effector proteins, investigating the variations in the amino acid sequence and structures of GTPases often provides insights into regulatory mechanisms that are more GTPase-specific. TCL/RhoJ is a Rho GTPase most closely related to Cdc42 and TC10; however, its nucleotide exchange activity is distinctly influenced by N-terminal amino acids 17-20 and the more distal amino acids 121-129. In this short study, we have further explored the differences between TCL and its homologue TC10 and show that its unique mode of allosteric regulation requires broader diversification of its amino acid sequence than previously appreciated.