Fig. (6).

Potential mechanisms regulating Ras dimer formation and signaling. (a) Lipid anchors (¹⁷⁵KKKKKKSKTKC(Far)OMe) of two KRas C-terminal HVR’s placed in a lipid bilayer. The C-terminal amino acid residues are rendered in sticks and colored by residue number. The farnesyl group is in cyan (Far). The lipid bilayer head groups are shown in lines, with lipid tailed colored in gray and lipid head groups colored using the “atomic name” scheme; (b) Scaffold proteins such as galectins and integrins may facilitate Ras dimer formation. For example galectins may interact with Ras either directly (left) or through integrin (right) to cause Ras to dimerize or cluster. Relative positions of the proteins are putative and may not reflect the actual spatial arrangement; (c) Predicted G-domain interfaces for NRas-GDP (left) and KRas-GTP (middle and right). Figures were reproduced based on information in references (53; left) and (52; middle and right), respectively.