Identifying proteins in the autophagosomes by a proteomic approach
In this study we applied quantitative mass spectrometry analysis to identify autophagsome-associated proteins. We starved breast cancer cells expressing GFP-LC3 or treated them with rapamycin or concanamycin A, purified their autophagosomes by gradient centrifugation and analyzed the protein composition by mass spectrometry. We identified several hundred proteins in the purified autophagosomes. Interestingly, only a small subset of these was common for the starved cells and cells treated with rapamycin and concanamycin A. The known autophagosome-associated proteins, GABARAPL2 and p62/SQSTMN1, were among the common proteins. Notably, the majority of the autophagosome-associated proteins were specific to the insult applied. This suggests that an autophagosome selectively chooses the proteins to be degraded, instead of serving as a non-selective degradation mechanism. Importantly, we found 85 common autophagosome-associated proteins. We are currently testing by immune-staining if these could serve as new autophagosomal markers.
Document Type: Abstract
Affiliations: 1: Centre of Experimental Bioinformatics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark 2: Apoptosis Department and Centre for Genotoxic Stress, Institute for Cancer Biology, Danish Cancer Society, 2100 Copenhagen, Denmark
Publication date: May 1, 2008