Phosphoinositide 3-kinases (PI3Ks) generate 3-phosphoinositide lipids in cell membranes. A variety of intracellular target proteins interact with these lipids via specific lipid-binding modules and, as a consequence, undergo changes in their localization and/or activity. In this way, PI3Ks participate in the regulation of mitogenesis, differentiation, survival, intracellular vesicular transport, cytoskeletal reorganization, and motility. Tyrosine kinases and Ras use PI3Ks as essential intracellular signal relay molecules. PI3Ks are heterodimeric enzymes consisting of a regulatory subunit in complex with a p110 catalytic subunit. Mammmals have genes encoding three distinct catalytic subunits (p110a, p110ß, and p110d and three regulatory subunits (p85a, p85ß, and p55d). All of the p110 isoforms are capable of interacting with each type of regulatory subunit. They are also similarly recruited to phosphotyrosine complexes and have, at least in vitro, the same lipid substrate specificity. However, it is becoming increasingly clear that PI3K isoforms differ in their interaction with Ras and regulation of lipid kinase activity, and in their protein kinase activities. Several groups have provided evidence that p110 isoforms have nonredundant functions in the regulation of cell proliferation, survival, actin cytoskeleton reorganization, and migration downstream of given receptors. This antibody is specific for the carboxy teminal end of p110d that is expressed predominantly in leukocytes.
This antibody was prepared from whole rabbit serum produced by repeated immunizations with a synthetic peptide corresponding to a region near the C-terminal of mouse PI3K p110d. This sequence is identical in both mouse and human.