Autophagy takes an alternative pathway.
ATG5 and ATG7 are considered as essential molecules for induction of macroautophagy. However, we found that cells lacking ATG5 or ATG7 can still form autophagosomes/autolysosomes and perform autophagy-mediated protein degradation when subjected to certain stresses. Although lipidation of LC3 is accepted to be a good indicator of macroautophagy, it did not occur during the ATG5/ATG7-independent alternative macroautophagy. Unlike conventional macroautophagy, autophagosomes seemed to be generated in a Rab9-dependent manner by the fusion of the phagophore with vesicles derived from the trans-Golgi and late endosomes. Mammalian macroautophagy can occur via at least two different pathways, which are an ATG5/ATG7-dependent conventional pathway and an ATG5/ATG7-independent alternative pathway.
Shimizu
Shigeomi
S
Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan. shimizu.pcb@mri.tmd.ac.jp
Arakawa
Satoko
S
Nishida
Yuya
Y
D000818:Animals; D001343:Autophagy / Q000502:physiology*; D000071187:Autophagy-Related Protein 5; D000071193:Autophagy-Related Protein 7; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D044764:Ubiquitin-Activating Enzymes / Q000378:metabolism
C502778:ATG5 protein, human; D000071187:Autophagy-Related Protein 5; D008869:Microtubule-Associated Proteins; C509349:ATG7 protein, human; D000071193:Autophagy-Related Protein 7; D044764:Ubiquitin-Activating Enzymes