phosphatidylinositol 3-kinase signaling pathway phosphatidylinositol 3-kinase class II signaling pathway 2012-05-18T10:50:58Z PW:0000965 Phosphatidylinositol kinases represent a family of lipid kinases that phosphorylate the 3' position of the inositol ring in target substrates. They are grouped into three classes: class I further subdivided into subclass A and B, class II and class III. By far the best known and characterized is class I, particularly IA that signals downstream of receptor tyrosine kinases and engages the Akt family of kinases. pathway vpetri