title: Novel role of protein kinase C-delta Tyr 311 phosphorylation in vascular smooth muscle cell hypertrophy by angiotensin II.
abstract: We have shown previously that activation of protein kinase C-delta (PKC delta) is required for angiotensin II (Ang II)-induced migration of vascular smooth muscle cells (VSMCs). Here, we have hypothesized that PKC delta phosphorylation at Tyr(311) plays a critical role in VSMC hypertrophy induced by Ang II. Immunoblotting was used to monitor PKC delta phosphorylation at Tyr(311), and cell size and protein measurements were used to detect hypertrophy in VSMCs. PKC delta was rapidly (0.5 to 10.0 minutes) phosphorylated at Tyr(311) by Ang II. This phosphorylation was markedly blocked by an Src family kinase inhibitor and dominant-negative Src but not by an epidermal growth factor receptor kinase inhibitor. Ang II-induced Akt phosphorylation and hypertrophic responses were significantly enhanced in VSMCs expressing PKC delta wild-type compared with VSMCs expressing control vector, whereas the enhancements were markedly diminished in VSMCs expressing a PKC delta Y311F mutant. Also, these responses were significantly inhibited in VSMCs expressing kinase-inactive PKC delta K376A compared with VSMCs expressing control vector. From these data, we conclude that not only PKC delta kinase activation but also the Src-dependent Tyr(311) phosphorylation contributes to Akt activation and subsequent VSMC hypertrophy induced by Ang II, thus signifying a novel molecular mechanism for enhancement of cardiovascular diseases induced by Ang II.
authors.affiliation: Cardiovascular Research Center, Department of Physiology, Temple University School of Medicine, 3420 N Broad St, Philadelphia, PA 19140, USA.
authors.forename: Hidekatsu
authors.initials: H
authors.lastname: Nakashima
authors.forename: Gerald D
authors.initials: GD
authors.lastname: Frank
authors.forename: Heigoro
authors.initials: H
authors.lastname: Shirai
authors.forename: Akinari
authors.initials: A
authors.lastname: Hinoki
authors.forename: Sadaharu
authors.initials: S
authors.lastname: Higuchi
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Ohtsu
authors.forename: Kunie
authors.initials: K
authors.lastname: Eguchi
authors.forename: Archana
authors.initials: A
authors.lastname: Sanjay
authors.forename: Mary E
authors.initials: ME
authors.lastname: Reyland
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Dempsey
authors.forename: Tadashi
authors.initials: T
authors.lastname: Inagami
authors.forename: Satoru
authors.initials: S
authors.lastname: Eguchi
mesh_terms: D000595:Amino Acid Sequence; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001011:Aorta; D002478:Cells, Cultured; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism; D006984:Hypertrophy; D015151:Immunoblotting; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D010766:Phosphorylation; D051745:Protein Kinase C-delta / Q000235:genetics* / Q000378:metabolism*; D051381:Rats; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism; D014443:Tyrosine; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D044140:Receptor, Angiotensin, Type 1; D000804:Angiotensin II; D014443:Tyrosine; D019061:src-Family Kinases; D051745:Protein Kinase C-delta; D043802:GTP-Binding Protein alpha Subunits, Gq-G11