The class IA PI3Kd is expressed in endothelial and in white blood cells. Recently it was shown that the inactivation of PI3Kd in bone marrow mast cells (BBMCs) leads to defective stem cell factor-mediated proliferation, adhesion and migration of these cells, and to impaired allergen-IgE induced degranulation and cytokine release. In neutrophils a role for PI3Kd in TNFa-induced signaling was demonstrated by a reduction in Aktphosphorylation and PDK1 activity upon treatment with the d-specific inhibitor IC87114. The catalytic subunit carries a GST-Tag which facilitates the protein�s application in typical GST pull-down assays and the heterodimer was purified by affinity chromatography. The molecular weight for p110d chain is 120.2 kDa (without Tag) and the p85a chain 83.5 kDa.
