Ras GTPase

Acylation is used by the cell for diverse purposes, the most common being membrane association. The membrane affinity of soluble proteins is increased via acylation, which affects the localization and function of proteins. This is found for singly and dually lipidated proteins. The localization of doubly lipidated proteins is determined by dynamic palmitoylation and depalmitoylation. Palmitoylation is therefore a tool for regulating protein trafficking in the cell. The most prominent examples are the small Ras GTPases. 

The superfamily of GTPases with their more than hundred members are divided by sequence homologies, molecular weight and subimit structure into further (super)fa-milies. These are the families of the heterotrimeric G-proteins, the Ras/GTPase superfamily and the family of initiation and elongation factors (Fig. 5.13). 

The heterotrimeric G-proteins are built of three subunits, with the GTPase activity localized on the largest subunit (see 5.5). The members of the Ras/GTPases, in contrast, are monomeric proteins with a molecular weight of ca.20 kDa (see Chapter 9). 

Allin, C., Ahmadian, M. R., Wittinghofer, A., and Gerwert, K. (2001). Monitoring the GAP catalyzed H-Ras GTPase reaction at atomic resolution in real time. Proc. Natl. Acad. Sci. USA 98, 7754-7759. 

F. 7 PARKS LRRK2 structure tuid mutations. ANK, ankyrin repeat region LRR, leucine-rich repeat domain ROC, Ras of complex COR, C-terminal of Ras (GTPase) (Tan et al., 2(X)7). Scale is approximate... 

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