PIP4K2A Protein, Human (Active)

The PIP4K2A protein plays a multifaceted role in cellular regulation, catalyzing the phosphorylation of phosphatidylinositol 5-phosphate (PtdIns5P) at the fourth hydroxyl of the myo-inositol ring to generate phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). This protein exhibits both ATP- and GTP-dependent kinase activities, contributing to its versatile enzymatic repertoire, and may modulate cytosolic PtdIns5P levels in response to tyrosine phosphorylation activation. Additionally, PIP4K2A is essential for lysosome-peroxisome membrane contacts, influencing intracellular cholesterol transport by regulating peroxisomal PtdIns(4,5)P2 levels. In collaboration with PIP4K2B, it plays a role in mediating autophagy during nutrient stress, impacting autophagosome-lysosome fusion and cellular lipid metabolism. PIP4K2A's involvement in thrombopoiesis and megakaryocyte maturation, coupled with its negative regulation of insulin signaling through a catalytic-independent mechanism, further underscores its diverse functions in cellular processes. Interactions with PIP5Ks highlight its role in suppressing PIP5K-mediated PtdIns(4,5)P2 synthesis and insulin-dependent conversion to PtdIns(3,4,5)P3, revealing its intricate regulatory connections in cellular signaling pathways.