| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Papers In Press, published online ahead of print November 22, 2005
Biochemistry Dept., Juntendo University School of Medicine, Tokyo 113-8421
Corresponding Author: kominami{at}med.juntendo.ac.jp
In yeast, phosphatidylethanolamine is a target of the Atg8 modifier in ubiquitylation-like reactions essential for autophagy. Three human Atg8 homologs, LC3, GABARAP, and GATE-16, have been characterized as modifiers in reactions mediated by hAtg7 (an E1-like enzyme) and hAtg3 (an E2-like enzyme) as in yeast Atg8-lipidation, but their final targets have not been identified. The results of a recent study in which COS7 cells were incubated with [14C]ethanolamine for 48 hours suggested that phosphatidylethanolamine is a target of LC3. However, these results were not conclusive because of the long incubation time. To identify the phospholipid targets of Atg8 homologs, we reconstituted conjugation systems for mammalian Atg8 homologs in vitro using purified recombinant Atg proteins and liposomes. Each purified mutant Atg8 homolog with an exposed C-terminal Gly formed an E1-substrate intermediate with hAtg7 via a thioester bond in an ATP-dependent manner, and formed an E2-substrate intermediate with hAtg3 via a thioester bond dependent on ATP and hAtg7. A conjugated form of each Atg8 homolog was observed in the presence of hAtg7, hAtg3, ATP, and liposomes. In addition to phosphatidylethanolamine, in vitro conjugation experiments using synthetic phospholipid liposomes showed that phosphatidylserine is also a target of LC3, GABARAP, and GATE-16. In contrast, thin layer chromatography of phospholipids released on hAtg4B-digestion from endogenous LC3-phospholipid conjugate revealed that phosphatidylethanolamine, but not phosphatidylserine, is the predominant target phospholipid of LC3 in vivo. The discrepancy between in vitro and in vivo reactions suggested that there may be selective factor(s) involved in the endogenous LC3 conjugation system.
J. Biol. Chem, 10.1074/jbc.M505888200
Submitted on May 31, 2005
Accepted on November 22, 2005
Phosphatidylserine in addition to phosphatidylethanolamine is an in vitro target of the mammalian Atg8 modifiers, LC3, GABARAP and GATE-16
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  E. L. Axe, S. A. Walker, M. Manifava, P. Chandra, H. L. Roderick, A. Habermann, G. Griffiths, and N. T. Ktistakis Autophagosome formation from membrane compartments enriched in phosphatidylinositol 3-phosphate and dynamically connected to the endoplasmic reticulum J. Cell Biol., August 26, 2008; 182(4): 685 - 701. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Ichimura, T. Kumanomidou, Y.-s. Sou, T. Mizushima, J. Ezaki, T. Ueno, E. Kominami, T. Yamane, K. Tanaka, and M. Komatsu Structural Basis for Sorting Mechanism of p62 in Selective Autophagy J. Biol. Chem., August 15, 2008; 283(33): 22847 - 22857. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Oh-oka, H. Nakatogawa, and Y. Ohsumi Physiological pH and Acidic Phospholipids Contribute to Substrate Specificity in Lipidation of Atg8 J. Biol. Chem., August 8, 2008; 283(32): 21847 - 21852. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Fujita, T. Itoh, H. Omori, M. Fukuda, T. Noda, and T. Yoshimori The Atg16L Complex Specifies the Site of LC3 Lipidation for Membrane Biogenesis in Autophagy Mol. Biol. Cell, May 1, 2008; 19(5): 2092 - 2100. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Fujioka, N. N. Noda, K. Fujii, K. Yoshimoto, Y. Ohsumi, and F. Inagaki In Vitro Reconstitution of Plant Atg8 and Atg12 Conjugation Systems Essential for Autophagy J. Biol. Chem., January 25, 2008; 283(4): 1921 - 1928. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Hanada, N. N. Noda, Y. Satomi, Y. Ichimura, Y. Fujioka, T. Takao, F. Inagaki, and Y. Ohsumi The Atg12-Atg5 Conjugate Has a Novel E3-like Activity for Protein Lipidation in Autophagy J. Biol. Chem., December 28, 2007; 282(52): 37298 - 37302. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. P. Taylor and K. Kirkegaard Modification of Cellular Autophagy Protein LC3 by Poliovirus J. Virol., November 15, 2007; 81(22): 12543 - 12553. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Pankiv, T. H. Clausen, T. Lamark, A. Brech, J.-A. Bruun, H. Outzen, A. Overvatn, G. Bjorkoy, and T. Johansen p62/SQSTM1 Binds Directly to Atg8/LC3 to Facilitate Degradation of Ubiquitinated Protein Aggregates by Autophagy J. Biol. Chem., August 17, 2007; 282(33): 24131 - 24145. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-h. Zhu, C. Horbinski, F. Guo, S. Watkins, Y. Uchiyama, and C. T. Chu Regulation of Autophagy by Extracellular Signal-Regulated Protein Kinases During 1-Methyl-4-Phenylpyridinium-Induced Cell Death Am. J. Pathol., January 1, 2007; 170(1): 75 - 86. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| All ASBMB Journals | Molecular and Cellular Proteomics |
| Journal of Lipid Research | ASBMB Today |
