GTPase signaling module

In analyzing the temporal behavior of a biochemical switching molecule, we can study either of the equivalent models of the phosphorylation-dephosphorylation cycle or the GTPase signaling module. In particular, we are interested in the duration of each activation event at the single-molecule level. 

Kolyada, A. Y., Riley, K. N., and Herman, 1. M. (2003). Rho GTPase signaling modulates cell shape and contractile phenotype in an isoactin-specific manner. Am. J. Physiol. Cell Physiol. 285, C1116-C1121. 

McEntaffer, R. L., Natochin, M., and Artemyev, N. O. (1999). Modulation of transducin GTPase activity by chimeric RGS16 and RGS9 regulators of G protein signaling and the effector molecule. Biochemistry 38, 4931-4937. 

All signaling mechanisms must have this modulation feature to allow the possibility of control. For example, the Ras protein of mammalian cells is a membrane-bound GTPase. Mutations that decrease Ras s GTPase activity can contribute to uncontrolled growth (i.e., tumor formation) of mammalian cells. 

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