Phosphoinositide-3-Kinase Catalytic Beta Polypeptide (PIK3Cb)

Phosphoinositide 3-kinases (PI3Ks) phosphorylate the 3-prime OH position of the inositol ring of inositol lipids. They have been implicated as participants in signaling pathways regulating cell growth by virtue of their activation in response to various mitogenic stimuli. PI3Ks are composed of a 110-kD catalytic subunit, such as PIK3CB, and an 85-kD adaptor subunit.

The predicted 1,070-amino acid protein, called p110-beta by them, is 42% identical to that of bovine p110. Northern blot analysis revealed that the major 4.8-kb p110-beta transcript was expressed in several human and rodent cell lines, as well as in all mouse tissues tested. Minor larger transcripts were detected in some tissues and cell lines.