Macroautophagy | Regulation During Feeding, Fasting and Starvation

The video explores how fasting regulates macroautophagy, a process of cellular degradation and recycling. It explains the role of macroautophagy in energy generation during fasting and details the pathway involving autophagosomes and lysosomes. The regulation by mTOR and AMPK is discussed, highlighting their influence on autophagy activation. Nuclear changes during fasting, including the roles of transcription factors like TFEB, ZKSCAN3, and FXR, are covered. The video also touches on the JNK pathway's role in autophagic trafficking. Finally, it summarizes the effects of short-term and prolonged fasting on macroautophagy and chaperone-mediated autophagy.

What is the primary role of macroautophagy during fasting?

• To increase cell division

• To store excess energy

• To synthesize new proteins

• To recycle nutrient substrates

Which protein is involved in the initiation of the macroautophagy pathway?

• Beclin 1

• P62

• Ulk 1

• LC3

What is the role of LC3 in the macroautophagy pathway?

• It is involved in autophagosome elongation

• It acts as a cargo receptor

• It degrades cellular components

• It initiates autophagosome formation

What happens to mTOR complex 1 during fasting?

• It phosphorylates Ulk 1

• It is inhibited by AMPK

• It inhibits AMPK

• It becomes activated

How does AMPK influence macroautophagy during fasting?

• It inhibits Ulk 1

• It activates mTOR complex 1

• It phosphorylates and activates Ulk 1

• It decreases AMP levels

What is the function of calcineurin during fasting?

• It removes phosphate groups from TFEB

• It activates mTOR complex 1

• It phosphorylates TFEB

• It inhibits AMPK

Which transcription factor is a master regulator of lysosomal biogenesis?

• TFEB

• FXR

• PPAR alpha

• ZKSCAN3

Which transcriptional repressor is removed from the nucleus during fasting?

• PPAR alpha

• TFEB

• ZKSCAN3

• Ulk 1

During prolonged fasting, which type of autophagy becomes more prominent?

• Chaperone-mediated autophagy

• Macroautophagy

• Mitophagy

• Microautophagy

Why does chaperone-mediated autophagy become important during prolonged fasting?

• To enhance cell division

• To store excess nutrients

• To selectively degrade specific proteins

• To increase protein synthesis