Phosphatidylinositol 4-Kinaseβ Is Critical for Functional Association of rab11 with the Golgi Complex

Abstract

Phosphatidylinositol 4-kinaseβ (PI4Kβ) plays an essential role in maintaining the structural integrity of the Golgi complex. In a search for PI4Kβ-interacting proteins, we found that PI4Kβ specifically interacts with the GTP-bound form of the small GTPase rab11. The PI4Kβ-rab11 interaction is of functional significance because inhibition of rab11 binding to PI4Kβ abolished the localization of rab11 to the Golgi complex and significantly inhibited transport of vesicular stomatitis virus G protein from the Golgi complex to the plasma membrane. We propose that a novel function of PI4Kβ is to act as a docking protein for rab11 in the Golgi complex, which is important for biosynthetic membrane transport from the Golgi complex to the plasma membrane.