Identification of protein kinase D as a novel contraction-activated kinase linked to GLUT4-mediated glucose uptake, independent of AMPK.
Contraction-induced glucose uptake is only partly mediated by AMPK activation. We examined whether the diacylglycerol-sensitive protein kinase D (PKD; also known as novel PKC isoform mu) is also involved in the regulation of glucose uptake in the contracting heart. As an experimental model, we used suspensions of cardiac myocytes, which were electrically stimulated to contract or treated with the contraction-mimicking agent oligomycin. Induction of contraction at 4 Hz in cardiac myocytes or treatment with 1 microM oligomycin enhanced (i) autophosphorylation of PKD at Ser916 by 5.1- and 3.8-fold, respectively, (ii) phosphorylation of PKD's downstream target cardiac-troponin-I (cTnI) by 2.9- and 2.1-fold, respectively, and (iii) enzymatic activity of immunoprecipitated PKD towards the substrate peptide syntide-2 each by 1.5-fold. Although AMPK was also activated under these same conditions, in vitro phosphorylation assays and studies with cardiac myocytes from AMPKalpha2(-/-) mice indicated that activation of PKD occurs independent of AMPK activation. CaMKKbeta, and the cardiac-specific PKC isoforms alpha, delta, and epsilon were excluded as upstream kinases for PKD in contraction signaling because none of these kinases were activated by oligomycin. Stimulation of glucose uptake and induction of GLUT4 translocation in cardiac myocytes by contraction and oligomycin each were sensitive to inhibition by the PKC/PKD inhibitors staurosporin and calphostin-C. Together, these data elude to a role of PKD in contraction-induced GLUT4 translocation. Finally, the combined actions of PKD on cTnI phosphorylation and on GLUT4 translocation would efficiently link accelerated contraction mechanics to increased energy production when the heart is forced to increase its contractile activity.
Luiken
Joost J F P
JJ
Department of Molecular Genetics, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands. j.luiken@gen.unimaas.nl
Vertommen
Didier
D
Coort
Susan L M
SL
Habets
Daphna D J
DD
El Hasnaoui
Mohammed
M
Pelsers
Maurice M L
MM
Viollet
Benoit
B
Bonen
Arend
A
Hue
Louis
L
Rider
Mark H
MH
Glatz
Jan F C
JF
D055372:AMP-Activated Protein Kinases; D000818:Animals; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000378:metabolism; D003847:Deoxyglucose / Q000378:metabolism; D004558:Electric Stimulation; D004789:Enzyme Activation; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009097:Multienzyme Complexes / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D009119:Muscle Contraction / Q000187:drug effects; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D009281:Naphthalenes / Q000494:pharmacology; D009840:Oligomycins / Q000494:pharmacology; D010455:Peptides / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects; D019311:Staurosporine / Q000494:pharmacology; D019210:Troponin I / Q000378:metabolism
D051275:Glucose Transporter Type 4; D036341:Intercellular Signaling Peptides and Proteins; D009097:Multienzyme Complexes; D009281:Naphthalenes; D009840:Oligomycins; D010455:Peptides; D047428:Protein Kinase Inhibitors; C495694:Slc2a4 protein, rat; D019210:Troponin I; C063391:syntide-2; D003847:Deoxyglucose; C089212:protein kinase D; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D055372:AMP-Activated Protein Kinases; D019311:Staurosporine; C058819:calphostin C; D005947:Glucose