phosphatidylinositol 4-kinase type 2-beta

Function

• together with PI4K2A & the type 3 PI4Ks (PIK4CA & PIK4CB), contributes to the overall PI4-kinase activity of cell
• especially significant in plasma membrane, endosomal & Golgi compartments
• phosphorylation of phosphatidylinositol (PI) to PI4P is the 1st committed step in the generation of PIP2, a precursor of the second messenger inositol 1,4,5-trisphosphate (IP3)
• contributes to the production of IP3 in stimulated cells
• role in the regulation of vesicular trafficking

ATP + 1-phosphatidyl-1D-myo-inositol
                 <-->
ADP + 1-phosphatidyl-1D-myo-inositol 4-phosphate

Structure

• belongs to the PI3/PI4-kinase family, type II PI4K subfamily
• contains 1 PI3K/PI4K domain

Compartment

• cytoplasm, membrane
• recruited & activated by membrane association
• binding to the microsomal membrane enhances activity
• mostly cytoplasmic
• also found associated with plasma membrane, Golgi & endosomes
• compared to PI4K2A, a larger fraction of PI4K2B is cytosolic due to a smaller extent of palmitoylation
• translocates to membranes where it is recruited by PDGF stimulation by a Rac-GTP-dependent mechanism

Expression

widely expressed

More general terms

• kinase or ATP-phosphotransferase

Database

• UniProt: http://www.uniprot.org/uniprot/Q8TCG2.html