title: Epigallocatechin gallate (EGCG) inhibits type II phosphatidylinositol 4-kinases: a key component in pathways of phosphoinositide turnover.
abstract: Type II phosphatidylinositol (PtdIns) 4-kinases produce PtdIns 4-phosphate, an early key signaling molecule in phosphatidylinositol cycle, which is indispensable for T cell activation. Type II PtdIns 4-kinase alpha and beta have similar biochemical properties. To distinguish these isoforms Epigallocatechin gallate (EGCG) has been evaluated as a specific inhibitor. EGCG is the major active catechin in green tea having anti-inflammatory, antiatherogenic and cancer chemopreventive properties. The precise mechanism of actions and molecular targets of EGCG in early signaling cascades are not well understood. In the present study, we have shown that EGCG inhibits type II PtdIns 4-kinases (α and β isoforms) and PtdIns 3-kinase activity in vitro. EGCG directly bind to both alpha and beta isoforms of type II PtdIns 4-kinases with a Kd of 2.62 μM and 1.02 μM, respectively. Type II PtdIns 4-kinase-EGCG complex have different binding pattern at its excited state. Both isoforms showed significant change in helicity upon binding with EGCG. EGCG modulates its effect by interacting with ATP binding pocket; the residues likely to be involved in EGCG binding were predicted by Autodock. Our findings suggest that EGCG inhibits two isoforms and could be a key to regulate T cell activation.
authors.affiliation: Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India. ranjeet@scripps.edu
authors.forename: Ranjeet K
authors.initials: RK
authors.lastname: Sinha
authors.forename: Ronak Y
authors.initials: RY
authors.lastname: Patel
authors.forename: Naveen
authors.initials: N
authors.lastname: Bojjireddy
authors.forename: Anindya
authors.initials: A
authors.lastname: Datta
authors.forename: Gosukonda
authors.initials: G
authors.lastname: Subrahmanyam
mesh_terms: D019870:1-Phosphatidylinositol 4-Kinase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D001665:Binding Sites; D028241:Camellia sinensis / Q000737:chemistry; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D019169:Jurkat Cells; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000517:prevention & control; D010716:Phosphatidylinositols / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D016588:Anticarcinogenic Agents; D004791:Enzyme Inhibitors; D010716:Phosphatidylinositols; D020033:Protein Isoforms; D002392:Catechin; C045651:epigallocatechin gallate; D019870:1-Phosphatidylinositol 4-Kinase