Phosphatidylinositol-4,5-bisphosphate 3-kinase

In enzymology, a phosphatidylinositol-4,5-bisphosphate 3-kinase (EC 2.7.1.153) is an enzyme that catalyzes the chemical reaction:

ATP + 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate ${\displaystyle \rightleftharpoons }$ ADP + 1-phosphatidyl-1D-myo-inositol 3,4,5-trisphosphate

Thus, the two substrates of this enzyme are ATP and , whereas its two products are ADP and .

This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. The systematic name of this enzyme class is ATP:1-phosphatidyl-1D-myo-inositol-4,5-bisphosphate 3-phosphotransferase. This enzyme is also called type I phosphoinositide 3-kinase. This enzyme participates in 29 metabolic pathways: inositol phosphate metabolism, , , , apoptosis, VEGF signaling pathway, focal adhesion, , , , , , , , , , , Type II diabetes mellitus, colorectal cancer, renal cell carcinoma, pancreatic cancer, endometrial cancer, glioma, prostate cancer, melanoma, chronic myeloid leukemia, acute myeloid leukemia, small cell lung cancer, and non-small cell lung cancer.

Structural studies[]

As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes 2A4Z, 2A5U, 2CHW, 2CHX, 2CHZ, and 2V1Y.

Examples[]

Human genes encoding proteins with phosphatidylinositol-4,5-bisphosphate 3-kinase activity include:

• PIK3CA
• PIK3CB
• PIK3CD
• PIK3CG

References[]

• PC, Woscholski R, Parker PJ, Waterfield MD (2001). "Synthesis and function of 3-phosphorylated inositol lipids". Annu. Rev. Biochem. 70: 535–602. doi:10.1146/annurev.biochem.70.1.535. PMID 11395417.