A 150 kDa protein serine-threonine kinase that is found as a regulatory subunit of the class III phosphatidylinositol 3-kinases. The protein is believed to play an important role in the regulation of vesicular trafficking with the cell.

Synonyms: Phosphatidylinositol 3-Kinase, Regulatory Subunit, Polypeptide 4, p150, Class III Phosphatidylinositol 3-Kinase Regulatory Subunit, EC 2.7.11.1, Class III Phosphatidylinositol 3 Kinase Regulatory Subunit, Vacuolar Sorting Protein VPS15, Class III Phosphatidylinositol 3 Kinase, p150 Subunit, Vps15 Protein Kinase, Class III Phosphatidylinositol 3-Kinase, p150 Subunit, Protein Kinase, Vps15, Vacuolar Protein Sorting 15, Phosphoinositide-3-kinase, Regulatory Subunit 4, VPS15 Protein, Phosphoinositide 3 kinase, Regulatory Subunit 4