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
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
<templatestyles src="Module:Hatnote/styles.css"></templatestyles>
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
There are several types of Gi: Gia1, Gia2, Gia3 and Gia4
Gia1
Gia1 or Gi1 is encoded by the gene GNAI1.
Gia2
Gia2 or Gi2 is encoded by the gene GNAI2.
Gia3
Gia3 or Gi3 is encoded by the gene GNAI3.
See also
References
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ GeneGlobe -> GHRH Signaling Retrieved on May 31, 2009
External links
- Gi alpha Subunit at the US National Library of Medicine Medical Subject Headings (MeSH)
