Protein kinase C-zeta as a downstream effector of phosphatidylinositol 3-kinase during insulin stimulation in rat adipocytes - Potential role in glucose transport

被引:401
作者
Standaert, ML
Galloway, L
Karnam, P
Bandyopadhyay, G
Moscat, J
Farese, RV
机构
[1] JA HALEY VET HOSP,RES SERV VAR 151,TAMPA,FL 33612
[2] UNIV S FLORIDA,COLL MED,DEPT INTERNAL MED,TAMPA,FL 33612
[3] UNIV S FLORIDA,COLL MED,DEPT BIOCHEM MOL BIOL,TAMPA,FL 33612
[4] UNIV AUTONOMA MADRID,CTR BIO MOL SERVERO OCHOA,MADRID 280049,SPAIN
关键词
D O I
10.1074/jbc.272.48.30075
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Insulin provoked rapid increases in enzyme activity of immunoprecipitable protein kinase C-zeta (PKC-zeta) in rat adipocytes. Concomitantly, insulin provoked increases in P-32 labeling of PKC-zeta both in intact adipocytes and during in vitro assay of immunoprecipitated PKC-zeta; the latter probably reflected autophosphorylation, as it was inhibited by the PKC-zeta pseudosubstrate. Insulin-induced activation of immunoprecipitable PKC-zeta was inhibited by LY294002 and wortmannin; this suggested dependence upon phosphatidylinositol (PI) 3-kinase. Accordingly, activation of PI 3-kinase by a pYXXM-containing peptide in vitro resulted in a wortmannin-inhibitable increase in immunoprecipitable PKC-zeta enzyme activity, Also, PI-3,4-(PO4)(2), PI-3,4,5-(PO4)(3), and PI-4,5-(PO4)(2) directly stimulated enzyme activity and autophosphoralytion in control PKC-zeta immunoprecipitates to levels observed in insulin-treated PKC-zeta immunoprecipitates. In studies of glucose transport, inhibition of immunoprecipitated PKC-zeta enzyme activity in vitro by both the PKC-zeta pseudosubstrate and RO 31-8220 correlated well with inhibition of insulin stimulated glucose transport in intact adipocytes. Also, in adipocytes transiently expressing hemagglutinin antigen-tagged GLUT4, co-transfection of wild-type or constitutive PKC-zeta stimulated hemagglutinin antigen-GLUT4 translocation, whereas dominant-negative PKC-zeta partially inhibited it. Our findings suggest that insulin activates PKC-zeta through PI 3-kinase, and PKC-zeta may act as a downstream effector of PI 3-kinase and contribute to the activation of GLUT4 translocation.
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页码:30075 / 30082
页数:8
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共 23 条
  • [21] PROTEIN-KINASE-C INHIBITORS BLOCK INSULIN AND PMA-STIMULATED HEXOSE-TRANSPORT IN ISOLATED RAT ADIPOCYTES AND BC3H-1 MYOCYTES
    STANDAERT, ML
    BUCKLEY, DJ
    ISHIZUKA, T
    HOFFMAN, JM
    COOPER, DR
    POLLET, RJ
    FARESE, RV
    [J]. METABOLISM-CLINICAL AND EXPERIMENTAL, 1990, 39 (11): : 1170 - 1179
  • [22] The phosphatidylinositol 3-kinase inhibitor, wortmannin, inhibits insulin-induced activation of phosphatidylcholine hydrolysis and associated protein kinase C translocation in rat adipocytes
    Standaert, ML
    Avignon, A
    Yamada, K
    Bandyopadhyay, G
    Farese, RV
    [J]. BIOCHEMICAL JOURNAL, 1996, 313 : 1039 - 1046
  • [23] ISOENZYME SPECIFICITY OF BISINDOLYLMALEIMIDES, SELECTIVE INHIBITORS OF PROTEIN-KINASE-C
    WILKINSON, SE
    PARKER, PJ
    NIXON, JS
    [J]. BIOCHEMICAL JOURNAL, 1993, 294 : 335 - 337