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Cambridge Institute for Medical Research

 

Glucose starvation can activate cellular autophagy, but the exact mechanisms of this have been unclear. PhD student Cansu Karabiyik and colleagues from the Rubinsztein lab have recently uncovered a phosphorylation pathway involving both proteins and lipids which casts new light on this important regulatory process. Their publication in Developmental Cell  shows how AMP-activated protein kinase, a sensor of cellular energy levels, activates the protein kinase ULK1, which, in turn, activates the lipid kinase PIKfyve on recycling endosomes. The resultant PI(5)P lipid then plays a role in recruiting proteins key to the biogenesis of autophagosomes. This newly-discovered pathway is distinct from canonical autophagosome generation which requires the lipid PI(3)P.