Ionic control of small GTPase HRas using calmodulin.

HRas is a small GTPase that plays physiologically important roles in various intracellular signal transduction processes, such as cell growth and proliferation. The structure and action mechanisms of HRas have been well-characterized, leading to widespread its use as a molecular switch in bionanomachines. calmodulin, a calcium ion-binding protein, acts as an ion-binding molecular switch and activates the target enzymes.

Photocontrol of small GTPase Ras fused with a photoresponsive protein.

The small GTPase Ras plays an important role in intracellular signal transduction and functions as a molecular switch. In this study, we used a photoresponsive protein as the molecular regulatory device to photoregulate Ras GTPase activity. Photo zipper (PZ), a variant of the photoresponsive protein Aureochrome1 developed by Hisatomi et al.