Arabidopsis homologues of the autophagy protein Atg8 are a novel family of microtubule binding proteins.
Autophagy is the non-selective transport of proteins and superfluous organelles destined for degradation to the vacuole in fungae, or the lysosome in animal cells. Some of the genes encoding components of the autophagy pathway are conserved in plants, and here we show that Arabidopsis homologues of yeast Atg8 (Apg8/Aut7) and Atg4 (Apg4/Aut2) partially complement the yeast deletion strains. The yeast double mutant, a deletion strain with respect to both Atg8 and Atg4, could not be complemented by Arabidopsis Atg8, indicating that Arabidopsis Atg8 requires Atg4 for its function. Moreover, Arabidopsis Atg8 and Arabidopsis Atg4 interact directly in a two-hybrid assay. Interestingly, Atg8 shows significant homology with the microtubule binding light chain 3 of MAP1A and B, and here we show that Arabidopsis Atg8 binds microtubules. Our results demonstrate that a principle component of the autophagic pathway in plants is similar to that in yeast and we suggest that microtubule binding plays a role in this process.
Ketelaar
Tijs
T
The Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, University of Durham, South Road, Durham DH1 3LE, UK.
Voss
Christiane
C
Dimmock
Simon A
SA
Thumm
Michael
M
Hussey
Patrick J
PJ
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001343:Autophagy / Q000235:genetics* / Q000502:physiology; D005816:Genetic Complementation Test; D008869:Microtubule-Associated Proteins / Q000235:genetics* / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D017385:Sequence Homology; D020798:Two-Hybrid System Techniques
D029681:Arabidopsis Proteins; D008869:Microtubule-Associated Proteins; D009842:Oligopeptides; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; C587254:asparagyl-tyrosyl-glutaminyl-glutaminyl-asparagine