Alignment of the most prominent human Rho GTPases. RhoA, Rac1, Cdc42 and RhoH were aligned using the ClustalW alignment program . Conserved residues are presented in red and RhoH specific amino acids are depicted in blue. The ITAM-like motif in RhoH comprising the sequence YxxA(X)6YxxA is underlined. Gray-shaded boxes mark the phosphate-binding loop, and switch I and switch II regions, respectively. The Rho family specific insertion motif that is absent in the other members of the Ras superfamily, is shown in bold typing.