Regulation of the autophagy protein LC3 by phosphorylation.
Macroautophagy is a major catabolic pathway that impacts cell survival, differentiation, tumorigenesis, and neurodegeneration. Although bulk degradation sustains carbon sources during starvation, autophagy contributes to shrinkage of differentiated neuronal processes. Identification of autophagy-related genes has spurred rapid advances in understanding the recruitment of microtubule-associated protein 1 light chain 3 (LC3) in autophagy induction, although braking mechanisms remain less understood. Using mass spectrometry, we identified a direct protein kinase A (PKA) phosphorylation site on LC3 that regulates its participation in autophagy. Both metabolic (rapamycin) and pathological (MPP(+)) inducers of autophagy caused dephosphorylation of endogenous LC3. The pseudophosphorylated LC3 mutant showed reduced recruitment to autophagosomes, whereas the nonphosphorylatable mutant exhibited enhanced puncta formation. Finally, autophagy-dependent neurite shortening induced by expression of a Parkinson disease-associated G2019S mutation in leucine-rich repeat kinase 2 was inhibited by dibutyryl-cyclic adenosine monophosphate, cytoplasmic expression of the PKA catalytic subunit, or the LC3 phosphorylation mimic. These data demonstrate a role for phosphorylation in regulating LC3 activity.
Cherra
Salvatore J
SJ
Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
Kulich
Scott M
SM
Uechi
Guy
G
Balasubramani
Manimalha
M
Mountzouris
John
J
Day
Billy W
BW
Chu
Charleen T
CT
D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D001343:Autophagy / Q000502:physiology*; D003994:Bucladesine / Q000378:metabolism; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D010588:Phagosomes / Q000378:metabolism; D010766:Phosphorylation; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D020123:Sirolimus / Q000494:pharmacology
D000903:Antibiotics, Antineoplastic; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D011993:Recombinant Fusion Proteins; D003994:Bucladesine; D017868:Cyclic AMP-Dependent Protein Kinases; D020123:Sirolimus