Autophagy is upregulated in nutrient-starved cells. The key kinase that is INHIBITED during starvation to permit autophagy initiation is:

• A AMPK (AMP-activated protein kinase)
• B Beclin-1 kinase complex
• C ULK1 (Unc-51-like autophagy activating kinase 1)
• D mTORC1 (mechanistic target of rapamycin complex 1) ✓

Explanation

mTORC1 is the master inhibitor of autophagy under nutrient-replete conditions; it phosphorylates and inactivates the ULK1 autophagy-initiating complex. During starvation, mTORC1 activity falls, allowing ULK1 to become active and initiate autophagosome formation. AMPK is activated by energy depletion and promotes autophagy by inhibiting mTORC1 and activating ULK1 directly. Beclin-1 is a positive regulator of autophagy, not an inhibitor.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.