Mechanisms of muscle plasticity: Exercise Flashcards
What does acute exercise elicit?
Acute exercise elicits rapid, but transient, increase in mRNA of given gene during recovery
Is a single bout of exercise enough to see adaptations?
Each bout of exercise is necessary for adaptation, but alone insufficient to alter phenotype
Where does the accumulation of protein come from?
Pulsed mRNA from each bout of exercise
Order of increase of exercise training: Mrna, proteins, exercise performance
True
What is PGC1- alpha and what does it do?
transcriptional coactivator important for turning on transcription factors which are sensitive to exercise
Participants completed 7 sessions of intense exercise (cycling) during 2-week intervention and Muscle biopsies from VL obtained 4 and 24 hours after the 1st, 3rd, 5th and 7th training session, what was shown?
Repeated transient bursts in mRNA (PGC1-alpha) precede increases in transcriptional and mito proteins (PGC1-alpha and CS)
Excitation-transcription coupling:
- Exercise results in diverse biochemical and biophysical stimuli within contracting muscle (varies)
- Leads to activation of integrated signalling networks & downstream targets (TFs & CoRs)
- Relative activation of pathways & downstream targets dependent on exercise FITT
How does transcription regulation occur?
Transcription regulation occurs via change in [protein], localization, or activity of TFs & CoRs
What to the TFs and CoRs stimulated by exercise do?
- TFs and CoRs stimulated by exercise demonstrate selective activation of gene promoters
- TFs and CoRs integrate contractile stimuli into molecular programming of gene expression
When PGC1-aplha is accetlyated and unphosphoralted what happens?
Has a low level of activity
From gym to genes?
Contraction-induced adaptations to exercise training, and modulators of
gene expression in skeletal muscle, that ultimately drive alterations in
phenotype and lead to functional improvements in exercise performance (MITOCHONDRIAL BIOGENIS AND MUSCL HYPERTROPHY)
How does the regulation and expression of PGC1-alpha work?
- Numerous transcription factors bind to regulatory sites in PGC-1α promoter
- PGC-1α can coactivate TFs that bind PGC-1α promoter = autoregulation
- Signals that enhance or repress PGC-1α activity can thus affect PGC-1α transcription
At rest where is the majority of PGC1-alpha?
in the cytosol of human skeletal muscle
How does acute exercise affect nuclear PGC1-alpha?
Nuclear PGC-1α [protein] increased 3 hours
into recovery from acute max cycling exercise (changing location)
How does acute exercise affect mitochondrial biogenesis?
3 hours of recovery after exercise coincided with increased mRNA
expression of mitochondrial genes, followed by increase in mitochondrial
[protein] & enzyme activity, and PGC-1α [protein] after 24 hours recovery
