INVESTIGADORES
REY Osvaldo
artículos
Título:
G protein-coupled receptor-mediated phosphorylation of the activation loop of protein kinase D: dependence on plasma membrane translocation and protein kinase Cepsilon.
Autor/es:
REY O, REEVE JR JR, ZHUKOVA E, SINNETT-SMITH J, ROZENGURT E.
Revista:
JOURNAL OF BIOLOGICAL CHEMISTRY
Editorial:
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Referencias:
Año: 2004 p. 34361 - 34372
ISSN:
0021-9258
Resumen:
Protein kinase D (PKD) is a serine/threonine protein kinase activated
by G protein-coupled receptor (GPCR) agonists through an incompletely
characterized mechanism that includes its reversible plasma membrane
translocation and activation loop phosphorylation via a protein kinase
C (PKC)-dependent pathway. To gain a better understanding of the
mechanism regulating the activation of PKD in response to GPCR
stimulation, we investigated the role of its rapid plasma membrane
translocation on its activation loop phosphorylation and identified the
endogenous PKC isozyme that mediates that event in vivo. We had found
that the activation loop of a PKD mutant, with reduced affinity for
diacylglycerol and phorbol esters, was only phosphorylated upon its
plasma membrane association. We also found that the activation loop
phosphorylation and rapid plasma membrane dissociation of PKD were
inhibited either by preventing the plasma membrane translocation of
PKCepsilon, through abolition of its interaction with receptor for
activated C kinase, or by suppressing the expression of PKCepsilon via
specific small interfering RNAs. Thus, this study demonstrates that the
plasma membrane translocation of PKD, in response to GPCR stimulation,
is necessary for the PKCepsilon-mediated phosphorylation of the
activation loop of PKD and that this event requires the translocation
of both kinases to the plasma membrane. Based on these and previous
results, we propose a model of GPCR-mediated PKD regulation that
integrates its changes in distribution, catalytic activity, and
multisite phosphorylation.