Guanine exchange factor

Barac, A., Basile, J., Vazquez-Prado, J., Gao, Y., Zheng, Y., and Gutkind, J. S. (2004). Direct interaction of p21-activated kinase 4 with PDZ-RhoGEF, a G protein-linked Rho guanine exchange factor. J. Biol. Chem. 279, 6182-6189. 

Chang, Y. C., Lee, H. H., Chen, Y. J., Bokoch, G. M., and Chang, Z. F. (2006). Contribution of guanine exchange factor HI in phorbol ester-induced apoptosis. Cell Death Differ. 13, 2023-2032. 

Fig. 15.1.2. The GTPase cycle showing activation of GTPase by guanine exchange factors (GEFs) in the presence of GTP and inactivation by hydrolysis of GTP to GDP in the presence of GTPase activating proteins (GAPs).

Cyclic AMP-binding Guanine Nucleotide Exchange Factors... 

Guanine nucleotide exchange factors (GEFs) are proteins which catalyse the release of nucleotide bound to small GTPases. 

Vav proteins are guanine nucleotide exchange factors (GEF) for monomeric GTPases. Tire Vav proteins belong to the DBL family of Rho GEFs and have an important role in regulating early events in receptor signalling. 

Guanine nucleotide exchange factors other than hSos have also been found to activate Ras, as have other effectors (see Table 8.2). These may interact with unique sequences in the effector loop. The question remains, however, as to how many different effectors can attach to activated Ras and what determines the level of their priority. 

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