Reaction: GTP + H2O = GDP + phosphate
Systematic name: GTP phosphohydrolase (signalling)
Comments: This group comprises GTP-hydrolysing systems, where GTP and GDP alternate in binding. This group includes stimulatory and inhibitory G-proteins such as Gs, Gi, Go and Golf, targetting adenylate cyclase and/or K+ and Ca2+ channels; Gq stimulating phospholipase C; transducin activating cGMP phosphodiesterase; gustducin activating cAMP phosphodiesterase. Golf is instrumental in odour perception, transducin in vision and gustducin in taste recognition. At least 16 different α subunits (39-52 kDa), 5 β subunits (36 kDa) and 12 γ subunits (6-9 kDa) are known.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:
References:
1. Neer, E.J. Heterotrimeric G proteins: organizers of transmembrane signals. Cell 80 (1995) 249-259. [PMID: 7834744]
2. Sprang, S.R. G protein mechanisms: insights from structural analysis. Annu. Rev. Biochem. 66 (1997) 639-678. [PMID: 9242920]
3. Bondarenko, V.A., Deasi, M., Dua, S., Yamazaki, M., Amin, R.H., Yousif, K.K., Kinumi, T., Ohashi, M., Komori, N., Matsumoto, H., Jackson, K.W., Hayashi, F., Usukura, J., Lipikin, V.M. and Yamazaki, A. Residues within the polycationic region of cGMP phosphodiesterase γ subunit crucial for the interaction with transducin α subunit. Identification by endogenous ADP-ribosylation and site-directed mutagenesis. J. Biol. Chem. 272 (1997) 15856-15864. [PMID: 9188484]
4. Ming, D., Ruiz-Avila, L. and Margolskee, R.F. Characterization and solubilization of bitter-responsive receptors that couple to gustducin. Proc. Natl. Acad. Sci. USA 95 (1998) 8933-8938. [PMID: 9671782]