A1 Refereed original research article in a scientific journal
Cdc48/p97 and Shp1/p47 regulate autophagosome biogenesis in concert with ubiquitin-like Atg8
Authors: Krick R, Bremer S, Welter E, Schlotterhose P, Muehe Y, Eskelinen EL, Thumm M
Publisher: ROCKEFELLER UNIV PRESS
Publication year: 2010
Journal: Journal of Cell Biology
Journal name in source: JOURNAL OF CELL BIOLOGY
Journal acronym: J CELL BIOL
Volume: 190
Issue: 6
First page : 965
Last page: 973
Number of pages: 9
ISSN: 0021-9525
DOI: https://doi.org/10.1083/jcb.201002075
Abstract
The molecular details of the biogenesis of double-membraned autophagosomes are poorly understood. We identify the Saccharomyces cerevisiae AAA-adenosine triphosphatase Cdc48 and its substrate-recruiting cofactor Shp1/Ubx1 as novel components needed for autophagosome biogenesis. In mammals, the Cdc48 homologue p97/VCP and the Shp1 homologue p47 mediate Golgi reassembly by extracting an unknown mono-ubiquitinated fusion regulator from a complex. We find no requirement of ubiquitination or the proteasome system for autophagosome biogenesis but detect interaction of Shp1 with the ubiquitin-fold autophagy protein Atg8. Atg8 coupled to phosphatidylethanolamine ( PE) is crucial for autophagosome elongation and, in vitro, mediates tethering and hemifusion. Interaction with Shp1 requires an FK motif within the N-terminal non-ubiquitin-like Atg8 domain. Based on our data, we speculate that autophagosome formation, in contrast to Golgi reassembly, requires a complex in which Atg8 functionally substitutes ubiquitin. This, for the first time, would give a rationale for use of the ubiquitin-like Atg8 during macroautophagy and would explain why Atg8-PE delipidation is necessary for efficient macroautophagy.
The molecular details of the biogenesis of double-membraned autophagosomes are poorly understood. We identify the Saccharomyces cerevisiae AAA-adenosine triphosphatase Cdc48 and its substrate-recruiting cofactor Shp1/Ubx1 as novel components needed for autophagosome biogenesis. In mammals, the Cdc48 homologue p97/VCP and the Shp1 homologue p47 mediate Golgi reassembly by extracting an unknown mono-ubiquitinated fusion regulator from a complex. We find no requirement of ubiquitination or the proteasome system for autophagosome biogenesis but detect interaction of Shp1 with the ubiquitin-fold autophagy protein Atg8. Atg8 coupled to phosphatidylethanolamine ( PE) is crucial for autophagosome elongation and, in vitro, mediates tethering and hemifusion. Interaction with Shp1 requires an FK motif within the N-terminal non-ubiquitin-like Atg8 domain. Based on our data, we speculate that autophagosome formation, in contrast to Golgi reassembly, requires a complex in which Atg8 functionally substitutes ubiquitin. This, for the first time, would give a rationale for use of the ubiquitin-like Atg8 during macroautophagy and would explain why Atg8-PE delipidation is necessary for efficient macroautophagy.
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