Phosphoinositide-3-Kinase Catalytic Delta Polypeptide (PIK3Cd)

Phosphoinositide 3-kinases (PI3Ks) phosphorylate the 3-prime OH position of the inositol ring of inositol lipids. The class I PI3Ks display a broad phosphoinositide lipid substrate specificity and include p110-alpha, p110-beta, and p110-gamma . p110-alpha and p110-beta interact with SH2/SH3-domain-containing p85 adaptor proteins and with GTP-bound Ras.

Like p110-alpha and p110-beta, p110-delta binds p85 adaptor proteins and GTP-bound Ras. These 3 class I PI3Ks were indistinguishable at the level of p85 adaptor protein selection or recruitment to activated receptor complexes. However, unlike p110-alpha, p110-delta does not phosphorylate p85, but instead has an autophosphorylation activity.