Figure 1.

Isoform- and activation-state dependent Ras reorientation on the plasma membrane. Computational and experimental data have provided support for distinct orientation states of Ras on the membrane. Earlier work showed that in the inactive (GDP-bound) state H-Ras contacts the membrane mostly via the lipid modified HVR (blue). However, in the active (GTP-bound) state the dominant conformations have helix α4 (pink) contacting the membrane. Follow up work further suggested that properties of helix α4 and the HVR can shift the reorientation balance. As described previously, switch III (sw III) comprises the β2-β3 loop (black loop) together with helix α5 (green) [21].