Class I PI3Ks are dual-specific lipid and protein kinases involved in numerous intracellular signaling pathways. Class IB PI3K, p110gamma, is mainly activated by seven-transmembrane G-protein-coupled receptors (GPCRs), through its regulatory subunit p101 and G-protein beta-gamma subunits [1].

1: Synthesis and function of 3-phosphorylated inositol lipids. Vanhaesebroeck B, Leevers SJ, Ahmadi K, Timms J, Katso R, Driscoll PC, Woscholski R, Parker PJ, Waterfield MD; Annu Rev Biochem. 2001;70:535-602. PMID:11395417