Gi alpha subunit
| guanine nucleotide-binding protein (G protein), alpha inhibiting activity polypeptide 1 | |
|---|---|
| Identifiers | |
| Symbol | GNAI1 |
| Entrez | 2770 |
| HUGO | 4384 |
| OMIM | 139310 |
| RefSeq | NM_002069 |
| UniProt | P63096 |
| Other data | |
| Locus | Chr. 7 q21-q22 |
| guanine nucleotide-binding protein (G protein), alpha inhibiting activity polypeptide 2 | |
|---|---|
| Identifiers | |
| Symbol | GNAI2 |
| Alt. symbols | GNAI2B |
| Entrez | 2771 |
| HUGO | 4385 |
| OMIM | 139360 |
| RefSeq | NM_002070 |
| UniProt | P04899 |
| Other data | |
| Locus | Chr. 3 p21 |
| guanine nucleotide-binding protein (G protein), alpha inhibiting activity polypeptide 3 | |
|---|---|
| Identifiers | |
| Symbol | GNAI3 |
| Entrez | 2773 |
| HUGO | 4387 |
| OMIM | 139370 |
| RefSeq | NM_006496 |
| UniProt | P08754 |
| Other data | |
| Locus | Chr. 1 p13 |
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 = Adenylate Cyclase inhibitor).
Contents
Receptors[edit]
The following G protein-coupled receptors couple to the Gi subunit:
- Acetylcholine M2 & M4 receptors
- Adenosine A1 & A3 receptors
- Adrenergic α2A, α2B, & α2C receptors
- Apelin receptors
- Calcium-sensing receptor
- Cannabinoid receptors (CB1 and CB2)
- Chemokine CXCR4 receptor
- Dopamine D2, D3, D4
- GABAB receptor
- Glutamate mGluR2, mGluR3, mGluR4, mGluR6, mGluR7, & mGluR8 receptors
- Histamine H3 & H4 receptors
- Melatonin MT1, MT2, & MT3 receptors
- Niacin receptors NIACR1 & NIACR2
- Opioid δ, κ, μ, & nociceptin receptors
- Prostaglandin EP1, EP3, FP, & TP receptors
- Serotonin 5-HT1 & 5-HT5 receptors
- Short chain fatty acid receptors: FFAR2 & FFAR3
- Somatostatin sst1, sst2, sst3, sst4 & sst5 receptors
- Trace amine-associated receptor 8
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]
- ^ 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. doi:10.1016/j.bbamem.2006.12.002. PMC 1993906. PMID 17258171.
- ^ Obál F, Krueger J (2001). "The somatotropic axis and sleep.". Rev Neurol (Paris) 157 (11 Pt 2): S12–5. PMID 11924022.
- ^ GeneGlobe -> GHRH Signaling Retrieved on May 31, 2009
External links[edit]
- Gi alpha Subunit at the US National Library of Medicine Medical Subject Headings (MeSH)
|
|
