Merck
  • Home
  • Search Results
  • AMPK/ULK1-mediated phosphorylation of Parkin ACT domain mediates an early step in mitophagy.

AMPK/ULK1-mediated phosphorylation of Parkin ACT domain mediates an early step in mitophagy.

Science advances (2021-04-09)
Chien-Min Hung, Portia S Lombardo, Nazma Malik, Sonja N Brun, Kristina Hellberg, Jeanine L Van Nostrand, Daniel Garcia, Joshua Baumgart, Ken Diffenderfer, John M Asara, Reuben J Shaw
ABSTRACT

The serine/threonine kinase ULK1 mediates autophagy initiation in response to various cellular stresses, and genetic deletion of ULK1 leads to accumulation of damaged mitochondria. Here we identify Parkin, the core ubiquitin ligase in mitophagy, and PARK2 gene product mutated in familial Parkinson's disease, as a ULK1 substrate. Recent studies uncovered a nine residue ("ACT") domain important for Parkin activation, and we demonstrate that AMPK-dependent ULK1 rapidly phosphorylates conserved serine108 in the ACT domain in response to mitochondrial stress. Phosphorylation of Parkin Ser108 occurs maximally within five minutes of mitochondrial damage, unlike activation of PINK1 and TBK1, which is observed thirty to sixty minutes later. Mutation of the ULK1 phosphorylation sites in Parkin, genetic AMPK or ULK1 depletion, or pharmacologic ULK1 inhibition, all lead to delays in Parkin activation and defects in assays of Parkin function and downstream mitophagy events. These findings reveal an unexpected first step in the mitophagy cascade.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
DAPI, for nucleic acid staining
Sigma-Aldrich
Antimycin A from Streptomyces sp.
Sigma-Aldrich
Rotenone, ≥95%
Sigma-Aldrich
Anti-Mitofusin-2 (N-Terminal) antibody produced in rabbit, affinity isolated antibody, buffered aqueous solution
Supelco
Phenformin hydrochloride, analytical standard
Millipore
ANTI-FLAG® antibody produced in rabbit, affinity isolated antibody, buffered aqueous solution
Sigma-Aldrich
Anti-Atg1/ULK1 antibody produced in rabbit, ~1 mg/mL, affinity isolated antibody, buffered aqueous solution