Small GTPase

Small GTPase

Small GTPases are a family of hydrolase enzymes that can bind and hydrolyze guanosine triphosphate (GTP). They are a form of G-proteins found in the cytosol which are homologous to the alpha subunit of heterotrimeric G-proteins, but unlike the alpha subunit of G proteins, a small GTPase can function independently as a hydrolase enzyme to bind to and hydrolyze a guanosine triphosphate (GTP) to form guanosine diphosphate (GDP). The most well-known members are the Ras GTPases and hence they are sometimes called Ras superfamily GTPases.

A typical G-protein is active when bound to GTP and inactive when bound to GDP (i.e. when the GTP is hydrolyzed to GDP). The GDP can be then replaced by free GTP. Therefore, a G-protein can be switched on and off. GTP hydrolysis is accelerated by GTPase activating proteins (GAPs), while GTP exchange is catalyzed by Guanine nucleotide exchange factors (GEFs). Activation of a GEF typically activates its cognate G-protein, while activation of a GAP results in inactivation of the cognate G-protein. Guanosine nucleotide dissociation inhibitors (GDI) maintain small GTP-ases in the inactive state.

Small GTPases regulate a wide variety of processes in the cell, including growth, cellular differentiation, cell movement and lipid vesicle transport.

Read more about Small GTPaseThe Ras Superfamily

Other articles related to "small gtpase, gtpases, gtpase":

FGD3
... factor activity • phospholipid binding • small GTPase binding • metal ion binding Cellular component • ruffle • cytoplasm • Golgi apparatus ...
GTP-binding Protein Regulators - Exchangers
... The inactive form of GTPases (GDP-form) are activated by a class of proteins called Guanosine nucleotide exchange factors (GEFs) ... catalyse nucleotide exchange by encouraging the release of GDP from the small GTPase (by displacement of the small GTPase-associated Mg2+ ion) and GDP's replacement by GTP (which is in at least a 10-fo ... Inactivation of the active small GTPase is achieved through hydrolysis of the GTP by the small GTPase's intrinsic GTP hydrolytic activity ...
RHOA
1096342 HomoloGene 68986 ChEMBL 6052 GeneCards RHOA Gene Gene Ontology Molecular function • GTPase activity • protein binding • GTP binding • myosin binding ...
Small GTPase - The Ras Superfamily
... core G domain, which provides essential GTPase and nucleotide exchange activity ... determine the functional specificity of the small GTPase, for example the 'Insert Loop', common to the Rho subfamily, specifically contributes to binding to effector proteins ...

Famous quotes containing the word small:

    I do not want to be covetous, but I think I speak the minds of many a wife and mother when I say I would willingly work as hard as possible all day and all night, if I might be sure of a small profit, but have worked hard for twenty-five years and have never known what it was to receive a financial compensation and to have what was really my own.
    Emma Watrous, U.S. inventor. As quoted in Feminine Ingenuity, ch. 8, by Anne L. MacDonald (1992)