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G proteins

Wednesday 7 July 2004

The heterotrimeric guanine nucleotide-binding proteins (G proteins) are signal transducers that communicate signals from many hormones, neurotransmitters, chemokines, and autocrine and paracrine factors.

The extracellular signals are received by members of a large superfamily of receptors with seven membrane-spanning regions that activate the G proteins, which route the signals to several distinct intracellular signaling pathways.

These pathways interact with one another to form a network that regulates metabolic enzymes, ion channels, transporters, and other components of the cellular machinery controlling a broad range of cellular processes, including transcription, motility, contractility, and secretion.

These cellular processes in turn regulate systemic functions such as embryonic development, gonadal development, learning and memory, and organismal homeostasis. Heterotrimeric G proteins play vital roles in cellular responses to external signals. The specificity of a G protein-receptor interaction is primarily mediated by the gamma subunit.

Guanine nucleotide-binding proteins (G proteins) transduce extracellular signals received by transmembrane receptors to effector proteins.

Members (subunits)

- alpha subunits

GNAS1 GNA1 GNA2 GNA3 GNA4 GNA5 GNA6 GNA7
GNA8 GNA9 GNA10 GNA11 GNA12 GNA13 GNA14 GNA15

- beta subunits

GNB1 GNB2

- gamma subunits

GNG1 GNG2 GNG3 GNG4 GNG5 GNG6 GNG7
GNG8 GNG9 GNG10 GNG11 GNG12 GNG13

Pathology

- mutations of GNAS1

GNAS1 Albright hereditary osteodystrophy
GNAS1 pseudohypoparathyroidism type Ia (PHP Ia)
GNAS1 pseudopseudohypoparathyroidism (PPHP)
GNAS1 pituitary tumors

References

- Bellaiche Y, Gotta M. Heterotrimeric G proteins and regulation of size asymmetry during cell division. Curr Opin Cell Biol. 2005 Dec;17(6):658-63. PMID: 16243504

- Robishaw JD, Berlot CH. Translating G protein subunit diversity into functional specificity. Curr Opin Cell Biol. 2004 Apr;16(2):206-9. PMID: 15196565

- Neves SR, Ram PT, Iyengar R. G protein pathways. Science. 2002 May 31;296(5573):1636-9. PMID: 12040175

- Farfel Z, Bourne HR, Iiri T. The expanding spectrum of G protein diseases. N Engl J Med. 1999 Apr 1;340(13):1012-20. PMID: 10099144