Open main menu

Gi alpha subunit

  (Redirected from Gi subunit)


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.[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.


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.

See alsoEdit


  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. doi:10.1016/j.bbamem.2006.12.002. PMC 1993906. PMID 17258171.
  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 linksEdit