Module 2 Flashcards
What changes in a muscle during aerobic exercise?
- PO2
- AMP
- ROS
- epi/norepinerphrine
- Ca2+
- NAD:NADH
What detects changes in PO2?
HIFα
What detects changes in AMP?
AMPK
What detects changes in ROS
p38mapk
What detects epinephrine and norepinephrine
CAMP
what detects changes in Ca2+
CAMK
List three key signaling molecules involved in exercise-induced angiogenesis.
ERR γ, ERRα, HIF1α
Explain the distinct roles of ERRγ and ERRα in regulating muscle vascularization.
ERRγ primarily influences baseline vascularization, while ERRα is activated by exercise and promotes increased VEGF production.
Describe the two primary mechanisms by which angiogenesis occurs.
Sprouting and splitting (intussusception)
Differentiate between capillary density and capillary number, and explain why both measurements are important.
Capillary density is the number of capillaries per unit area, indicating how packed the capillaries are. Capillary number is the number of capillaries per muscle fiber, indicating how well each fiber is supplied. Both give a more complete picture of vascularization.
Outline the signaling pathway by which calcium influences muscle fiber type.
Calcium → Calcineurin → NFAT → MEF2 → Gene expression changes
Explain the roles of calcineurin, NFAT, and MEF2 in determining slow-fiber characteristics.
Calcineurin activates NFAT, which then collaborates with MEF2 to induce the expression of genes that promote the slow-twitch phenotype.
How does the pattern of muscle contractions influence fiber type?
Higher frequency stimulation patterns tend to favor slow-twitch fibers.
List three transcription factors that PGC1α interacts with to promote mitochondrial biogenesis.
NRFs, PPARs, MEF2s
Describe the role of TFAM in mitochondrial biogenesis.
TFAM regulates the transcription and replication of mitochondrial DNA (mtDNA).
What are TOM and TIM, and what is their function?
Translocases of the outer membrane (TOM) and translocases of the inner membrane (TIM); they facilitate the import of proteins into mitochondria.
What does NuGEMPs stand for?
Nuclear-encoded mitochondrial proteins
What are mitochondria-derived peptides (MDPs)?
Signaling molecules produced by mitochondria.
Why are MDPs of interest in exercise physiology?
They may act as indicators of mitochondrial health and play roles in various physiological processes.
Give two examples of MDPs.
Humanin and MOTS-c
Explain the function of the UPRmt.
Unfolded protein response; a stress response that helps maintain proper protein folding within mitochondria.
How does mitochondrial respiration differ from mitochondrial-specific respiration?
Mitochondrial respiration is often expressed as oxygen consumption per gram of tissue, while mitochondrial-specific respiration (MAPR) measures ATP production rate in isolated mitochondria.
List the main steps in mitochondrial biogenesis, from exercise signal to mitochondrial assembly.
1) Exercise signals, 2) Signal detection, 3) PGC1α activation, 4) Transcription factor activation, 5) Nuclear events (transcription), 6) TFAM and mtDNA, 7) Mitochondrial transcription and translation, 8) Protein import, 9) Mitochondrial assembly
Give examples of exercise-induced signals that trigger mitochondrial biogenesis.
↓PO2, epinephrine/norepinephrine, AMP, Ca2+, ROS, NAD+/NADH ratio
What is the role of PGC1α? Is it a transcription factor?
PGC1α is a coactivator that enhances the activity of transcription factors
Name three transcription factors activated by PGC1α.
PPARs, NRFs, MEF2
What is TFAM, and what does it do?
Mitochondrial transcription factor A; it regulates the transcription and replication of mtDNA
Where is TFAM synthesized?
In the cytoplasm by ribosomes
Do mitochondria have their own DNA?
Yes, mtDNA
What are TOM and TIM?
Translocases of the outer membrane (TOM) and inner membrane (TIM); protein complexes that help import proteins into mitochondria
What does NuGEMPs stand for?
Nuclear-encoded mitochondrial proteins
Where are most mitochondrial proteins synthesized?
In the cytoplasm, encoded by nuclear DNA
