The role of phosphatidylinositol 4-kinases in vesicular transport

Phosphoinositide metabolism is involved in signal transduction, cytoskeletal organization and in vesicular transport. The main precursor for the different phosphoinositides, phosphatidylinositol(4)phosphate (PtdIns(4)P), is synthesized by phosphatidylinositol 4-kinase (PtdIns 4-kinase). Based on biochemical characterization the family of PtdIns 4-kinases has been divided in two types (II and III). Recently, two type III isoforms of this enzyme have been cloned and sequenced. Localization studies have shown a different location for these isoforms implying different functions for the PtdIns 4-kinases in vivo. In this chapter, we review the current data about PtdIns 4-kinases, and discuss the possible physiological function of PtdIns 4-kinase activity in vesicular transport.