Gi alpha subunit

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G protein subunit alpha i1
Identifiers
Symbol GNAI1
Entrez 2770
HUGO 4384
OMIM 139310
PDB 3UMR
RefSeq NM_002069
UniProt P63096
Other data
Locus Chr. 7 q21-q22
G protein subunit alpha i2
Identifiers
Symbol GNAI2
Entrez 2771
HUGO 4385
OMIM 139360
RefSeq NM_002070
UniProt P04899
Other data
Locus Chr. 3 p21
G protein subunit alpha i3
Identifiers
Symbol GNAI3
Entrez 2773
HUGO 4387
OMIM 139370
PDB 2ODE
RefSeq NM_006496
UniProt P08754
Other data
Locus Chr. 1 p13
G protein subunit alpha o1
Identifiers
Symbol GNAO1
Entrez 2775
HUGO 4389
OMIM 139311
RefSeq NM_020988
UniProt P09471
Other data
Locus Chr. 16 q13

Gi alpha subunit (Gαi, or Gi/G0 or Gi protein) is a heterotrimeric G protein subunit that inhibits the production of cAMP from ATP.[1] A mnemonic for remembering this subunit is to look at first letter (Gαi = Adenylyl Cyclase inhibitor).

Receptors[edit]

The following G protein-coupled receptors couple to the Gi subunit:

Function[edit]

Gi mainly inhibits the cAMP dependent pathway by inhibiting adenylate cyclase activity, decreasing the production of cAMP from ATP, which, in turn, results in decreased activity of cAMP-dependent protein kinase. Therefore, the ultimate effect of Gi is the opposite of cAMP-dependent protein kinase.

It is also attributed a minor role in activation of the phospholipase C pathway.[2] Growth hormone is required for normal postnatal growth, bone growth, regulatory effects on protein, carbohydrate, and lipid metabolism.[3] although this is mainly a function of the Gq alpha subunit.

Types[edit]

There are several types of Gi: Gia1, Gia2, Gia3 and Gia4

Gia1[edit]

Gia1 or Gi1 is encoded by the gene GNAI1.

Gia2[edit]

Gia2 or Gi2 is encoded by the gene GNAI2.

Gia3[edit]

Gia3 or Gi3 is encoded by the gene GNAI3.

See also[edit]

References[edit]

  1. ^ Birnbaumer L (April 2007). "Expansion of signal transduction by G proteins. The second 15 years or so: from 3 to 16 alpha subunits plus betagamma dimers". Biochim. Biophys. Acta. 1768 (4): 772–93. PMC 1993906Freely accessible. PMID 17258171. doi:10.1016/j.bbamem.2006.12.002. 
  2. ^ Obál F, Krueger J (2001). "The somatotropic axis and sleep.". Rev Neurol (Paris). 157 (11 Pt 2): S12–5. PMID 11924022. 
  3. ^ GeneGlobe -> GHRH Signaling[permanent dead link] Retrieved on May 31, 2009

External links[edit]