title: Increased atypical PKC activity in endurance-trained human skeletal muscle.
abstract: Exercise training may modulate protein content and enzyme activities in skeletal muscle. However, it is not known whether atypical protein kinase C (aPKC) is affected by training. Thus, we investigated aPKC, extracellular-regulated protein kinase 1/2 (ERK 1/2), and P38 mitogen-activated protein kinase (P38 MAPK) activities and expression in skeletal muscle from untrained and endurance-trained subjects at rest and after 20min of cycle exercise (80% of VO(2peak)). Activities of aPKC (P<0.05) and ERK 1/2 (P=0.06), but not phosphorylation of P38 MAPK, were higher in trained than in sedentary subjects at rest. Exercise increased the activities of ERK 1/2 (P<0.01) and aPKC (P<0.05) and the phosphorylation (Thr180/Tyr182) of P38 MAPK (P<0.01) similarly in muscle from trained and sedentary subjects. Protein expression of the kinases was similar in trained and sedentary muscle. The increased aPKC activity in exercise-trained subjects could be important in explaining the enhanced insulin action in these individuals.
authors.affiliation: Copenhagen Muscle Research Centre, Department of Human Physiology, Institute of Exercise and Sport Sciences, University of Copenhagen, DK-2100, Copenhagen, Denmark. jnnielsen@ifi.ku.dk
authors.forename: Jakob N
authors.initials: JN
authors.lastname: Nielsen
authors.forename: Christian
authors.initials: C
authors.lastname: Frøsig
authors.forename: Mini P
authors.initials: MP
authors.lastname: Sajan
authors.forename: Atsushi
authors.initials: A
authors.lastname: Miura
authors.forename: Mary L
authors.initials: ML
authors.lastname: Standaert
authors.forename: Drew A
authors.initials: DA
authors.lastname: Graham
authors.forename: Jørgen F P
authors.initials: JF
authors.lastname: Wojtaszewski
authors.forename: Robert V
authors.initials: RV
authors.lastname: Farese
authors.forename: Erik A
authors.initials: EA
authors.lastname: Richter
mesh_terms: D004789:Enzyme Activation / Q000502:physiology; D005080:Exercise Test; D006801:Humans; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000032:analysis / Q000502:physiology*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000032:analysis / Q000502:physiology*; D018482:Muscle, Skeletal / Q000166:cytology / Q000502:physiology*; D010806:Physical Education and Training / Q000379:methods; D010807:Physical Endurance / Q000502:physiology*; D011493:Protein Kinase C / Q000032:analysis / Q000502:physiology*; D012146:Rest / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: C115015:PKC-3 protein; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases