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document
Effect of resistance exercise contraction mode and protein supplementation on members of the STARS signalling pathway . 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 .
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Intervention_Physical
resistance exercise contraction mode
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Intervention_Physical
protein supplementation
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Intervention_Physical
resistance exercise
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Intervention_Physical
eccentric ( ECC ) or concentric ( CONC ) contractions
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Intervention_Educational
prolonged training
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Intervention_Physical
whey protein supplementation
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Intervention_Physical
exercise
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Intervention_Physical
ECC
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Intervention_Physical
CONC exercise
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Intervention_Physical
ECC exercise
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Intervention_Physical
CONC exercise
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Intervention_Physical
whey protein supplementation
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Intervention_Physical
acute exercise
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Intervention_Educational
accumulated training
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Outcome_Physical
STARS
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Outcome_Physical
SRF mRNA
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Outcome_Physical
MRTF-A mRNA with both ECC and CONC exercise
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Outcome_Physical
STARS protein
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Outcome_Physical
pSRF
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Outcome_Physical
MRTF-A protein
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Outcome_Physical
total SRF protein
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Outcome_Physical
whey protein supplementation .
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Outcome_Physical
acute stimulation of the STARS pathway