title: Effect of exercise and training on phospholemman phosphorylation in human skeletal muscle.
abstract: Phospholemman (PLM, FXYD1) is a partner protein and regulator of the Na(+)-K(+)-ATPase (Na(+)-K(+) pump). We explored the impact of acute and short-term training exercise on PLM physiology in human skeletal muscle. A group of moderately trained males (n = 8) performed a 1-h acute bout of exercise by utilizing a one-legged cycling protocol. Muscle biopsies were taken from vastus lateralis at 0 and 63 min (non-exercised leg) and 30 and 60 min (exercised leg). In a group of sedentary males (n = 9), we determined the effect of a 10-day intense aerobic cycle training on Na(+)-K(+)-ATPase subunit expression, PLM phosphorylation, and total PLM expression as well as PLM phosphorylation in response to acute exercise (1 h at ∼72% Vo(2peak)). Biopsies were taken at rest, immediately following, and 3 h after an acute exercise bout before and at the conclusion of the 10-day training study. PLM phosphorylation was increased both at Ser(63) and Ser(68) immediately after acute exercise (75%, P < 0.05, and 30%, P < 0.05, respectively). Short-term training had no adaptive effect on PLM phosphorylation at Ser(63) and Ser(68), nor was the total amount of PLM altered posttraining. The protein expressions of α(1)-, α(2)-,and β(1)-subunits of Na(+)-K(+)-ATPase were increased after training (113%, P < 0.05, 49%, P < 0.05, and 27%, P < 0.05, respectively). Whereas an acute bout of exercise increased the phosphorylation of PKCα/βII on Thr(638/641) pre- and posttraining, phosphorylation of PKCζ/λ on Thr(403/410) was increased in response to acute exercise only after the 10-day training. In conclusion, we show that only acute exercise, and not short-term training, increases phosphorylation of PLM on Ser(63) and Ser(68), and data from one-legged cycling indicate that this effect of exercise on PLM phosphorylation is not due to systemic factors. Our results provide evidence that phosphorylation of PLM may play a role in the acute regulation of the Na(+)-K(+)-ATPase response to exercise.
authors.affiliation: Dept. of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Boubacar
authors.initials: B
authors.lastname: Benziane
authors.forename: Ulrika
authors.initials: U
authors.lastname: Widegren
authors.forename: Sergej
authors.initials: S
authors.lastname: Pirkmajer
authors.forename: Jan
authors.initials: J
authors.lastname: Henriksson
authors.forename: Nigel K
authors.initials: NK
authors.lastname: Stepto
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Chibalin
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D010750:Phosphoproteins; C069141:phospholemman; D000254:Sodium-Potassium-Exchanging ATPase