Class I PI 3-kinases are a subgroup of the enzyme family,
phosphoinositide 3-kinase that possess a common protein domain structure, substrate specificity, and method of activation. Class I PI 3-kinases are further divided into two subclasses, class IA PI 3-kinases and class IB PI 3-kinases.
Class IA PI 3-kinases
Class IA PI 3-kinases are activated by
receptor tyrosine kinases (RTKs).
There are three catalytic subunits that are classified as class IA PI 3-kinases:
*
p110α
The phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (the HUGO-approved official symbol = PIK3CA; HGNC ID, HGNC:8975), also called p110α protein, is a class I PI 3-kinase catalytic subunit. The human p110α protein is en ...
*
p110β
*
p110δ
There are currently five regulatory subunits that are known to associate with class IA PI 3-kinases catalytic subunits:
*
p85α and
p85β
*
p55α and
p55γ
*
p50α
Class IB PI 3-kinases
Class IB PI 3-kinases are activated by
G-protein-coupled receptors (GPCRs).
The only known class IB PI 3-kinase catalytic subunit is
p110γ.
There are two known regulatory subunits for p110γ:
*
p101
*p84/
p87PIKAP.
See also
*
Phosphoinositide 3-kinase#Class I
*
Phosphoinositide 3-kinase inhibitor
References
*
*
*
EC 2.7.1
{{Cell-biology-stub