title: Effect of resistance exercise contraction mode and protein supplementation on members of the STARS signalling pathway.
abstract: The striated muscle activator of Rho signalling (STARS) pathway is suggested to provide a link between external stress responses and transcriptional regulation in muscle. However, the sensitivity of STARS signalling to different mechanical stresses has not been investigated. In a comparative study, we examined the regulation of the STARS signalling pathway in response to unilateral resistance exercise performed as either eccentric (ECC) or concentric (CONC) contractions as well as prolonged training; with and without whey protein supplementation. Skeletal muscle STARS, myocardian-related transcription factor-A (MRTF-A) and serum response factor (SRF) mRNA and protein, as well as muscle cross-sectional area and maximal voluntary contraction, were measured. A single-bout of exercise produced increases in STARS and SRF mRNA and decreases in MRTF-A mRNA with both ECC and CONC exercise, but with an enhanced response occurring following ECC exercise. A 31% increase in STARS protein was observed exclusively after CONC exercise (P < 0.001), while pSRF protein levels increased similarly by 48% with both CONC and ECC exercise (P < 0.001). Prolonged ECC and CONC training equally stimulated muscle hypertrophy and produced increases in MRTF-A protein of 125% and 99%, respectively (P < 0.001). No changes occurred for total SRF protein. There was no effect of whey protein supplementation. These results show that resistance exercise provides an acute stimulation of the STARS pathway that is contraction mode dependent. The responses to acute exercise were more pronounced than responses to accumulated training, suggesting that STARS signalling is primarily involved in the initial phase of exercise-induced muscle adaptations.
authors.affiliation: Section of Sport Science, Department of Public Health, Aarhus University, Dalgas Avenue 4, DK-8000 Aarhus C, Denmark. vissing@sport.au.dk
authors.forename: Kristian
authors.initials: K
authors.lastname: Vissing
authors.forename: Stine K
authors.initials: SK
authors.lastname: Rahbek
authors.forename: Severine
authors.initials: S
authors.lastname: Lamon
authors.forename: Jean
authors.initials: J
authors.lastname: Farup
authors.forename: Renae J
authors.initials: RJ
authors.lastname: Stefanetti
authors.forename: Marita A
authors.initials: MA
authors.lastname: Wallace
authors.forename: Mikkel H
authors.initials: MH
authors.lastname: Vendelbo
authors.forename: Aaron
authors.initials: A
authors.lastname: Russell
mesh_terms: D000328:Adult; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D019587:Dietary Supplements; D006801:Humans; D008297:Male; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D008894:Milk Proteins / Q000494:pharmacology*; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism; D055070:Resistance Training; D026362:Serum Response Factor / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000067816:Whey Proteins; D055815:Young Adult
chemical_list: C464441:ABRA protein, human; D004268:DNA-Binding Proteins; C431575:MRTFA protein, human; D008840:Microfilament Proteins; D008894:Milk Proteins; D015514:Oncogene Proteins, Fusion; D026362:Serum Response Factor; D015534:Trans-Activators; D014157:Transcription Factors; D000067816:Whey Proteins