Source:http://linkedlifedata.com/resource/umls/id/C0089793
MSH: An enzyme that catalyzes the conversion of phosphatidylinositol (PHOSPHATIDYLINOSITOLS) to phosphatidylinositol 4-phosphate, the first committed step in the biosynthesis of phosphatidylinositol 4,5-bisphosphate.,NCI: Phosphoinositide-4-Kinase, Catalytic, Beta Polypeptide, encoded by the PIK4CB gene, belongs to the PI3/PI4-kinase family. This protein phosphorylates phosphatidylinositol (PI) in the first committed step in the production of the second messenger inositol-1,4,5,-trisphosphate (PIP). It may regulate Golgi disintegration/reorganization during mitosis, possibly via its phosphorylation. Its enzymatic activity is inhibited by wortmannin. This protein is found in the outer membrane of mitochondria and membranes of the rough endoplasmic reticulum, and recruited to the Golgi complex by the small GTPase ARF to stimulate the synthesis of phosphatidylinositol 4,5-biphosphate (PIP2) on the Golgi complex. Two named isoforms exist resulting from alternative splicing. (from Swiss-Prot)