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Updated: May 11, 2026

Exploring the Regulation of Lipid Droplet Catabolism through Lipophagy
Published on: January 31, 2025
ULK1 induces autophagy by phosphorylating Beclin-1 and activating VPS34 lipid kinase
Ryan C Russell1, Ye Tian, Haixin Yuan
1Department of Pharmacology and Moores Cancer Center, University of California San Diego, La Jolla, California 92093, USA.
Abstract:
Autophagy is the primary cellular catabolic program activated in response to nutrient starvation. Initiation of autophagy, particularly by amino-acid withdrawal, requires the ULK kinases. Despite its pivotal role in autophagy initiation, little is known about the mechanisms by which ULK promotes autophagy. Here we describe a molecular mechanism linking ULK to the pro-autophagic lipid kinase VPS34. Following amino-acid starvation or mTOR inhibition, the activated ULK1 phosphorylates Beclin-1 on Ser 14, thereby enhancing the activity of the ATG14L-containing VPS34 complexes. The Beclin-1 Ser 14 phosphorylation by ULK is required for full autophagic induction in mammals and this requirement is conserved in Caenorhabditis elegans. Our study reveals a molecular link from ULK1 to activation of the autophagy-specific VPS34 complex and autophagy induction.
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