L2.1 Intracellular Signalling

Question 1

What are the 3 main cellular signals for Ca2+?

Answer 1

↑exercise → ↑Ca2+

1) CaMK 2
2) PhK → GPh → glycogenolysis → ATP
3) eEF2K → Inhibits eEf2 (increases protein synthesis) → ↓protein synthesis (don’t need proteins for exercise) → ↑ATP

Question 2

Function and effect of AMPK during exercise?

Answer 2

↑exercise →AMPK

Acts as energy sensors
In the heart & muscles:

↑Fat/glucose oxidation
Long term → GLUT 4 & ↑Mitochondria

In the hypothalamus:

↑Food intake

Inhibits anabolic pathways:

1) Pancreas: No insulin secretion
2) Liver: No FA synthesis, gluconeogenesis
3) Adipose tissues: No lipolysis & FA syn

Question 3

Effect of exercise on GLUT 4 expression?

Answer 3

↑exercise →↑GLUT4 expression

Muscles contract → (consumes ATP→AMPK)/↑(Ca2+→CAMK2)→HDAC5→↑GLUT4 expression→↑glucose uptake

Question 4

What are the roles of reactive oxygen species during exercise?

Answer 4

↑exercise → ↑ROS

Could cause damage at high []
Low [] → signal → 1) ↑Kinase activity; 2) ↓Phosphate activities

Therefore: Anti-oxidants are bad (good when ROS at high [])

Question 5

What is the mTOR pathway?

Answer 5

GH stimulation peptides → ↑IGF-1 → mTOR →

1) protein synthesis → Hypertrophy
2) Inhibits Foxo (causes muscle degeneration)

AMPK blunts effect of mTOR → due to ↓protein syn during exercise

But there will be↑protein syn after exercise