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. A mnemonic for remembering this subunit is to look at first letter (Gαi = Adenylyl Cyclase inhibitor).
The following G protein-coupled receptors couple to the Gi subunit:
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. Growth hormone is required for normal postnatal growth, bone growth, regulatory effects on protein, carbohydrate, and lipid metabolism. although this is mainly a function of the Gq alpha subunit.
There are several types of Gi: Gia1, Gia2, Gia3 and Gia4
Gia1 or Gi1 is encoded by the gene GNAI1.
Gia2 or Gi2 is encoded by the gene GNAI2.
Gia3 or Gi3 is encoded by the gene GNAI3.
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Wikipedia