Journal
EMBO JOURNAL
Volume 22, Issue 1, Pages 13-23Publisher
OXFORD UNIV PRESS
DOI: 10.1093/emboj/cdg007
Keywords
gene knockout; N-end rule; photosystem; protein degradation; stability
Categories
Ask authors/readers for more resources
Peptide deformylases (PDFs) have been discovered recently in eukaryotic genomes, and it appears that N-terminal methionine excision (NME) is a conserved pathway in all compartments where protein synthesis occurs. This work aimed at uncovering the function(s) of NME in a whole proteome, using the chloroplast-encoded proteins of both Arabidopsis thaliana and Chlamydomonas reinhardtii as model systems. Disruption of PDF1B in A.thaliana led to an albino phenotype, and an extreme sensitivity to the PDF-specific inhibitor actinonin. In contrast, a knockout line for PDF1A exhibited no apparent phenotype. Photosystem II activity in C.reinhardtii cells was substantially reduced by the presence of actinonin. Pulse-chase experiments revealed that PDF inhibition leads to destabilization of a crucial subset of chloroplast-encoded photosystem II components in C.reinhardtii. The same proteins were destabilized in pdf1b. Site-directed substitutions altering NME of the most sensitive target, subunit D2, resulted in similar effects. Thus, plastid NME is a critical mechanism specifically influencing the life-span of photosystem II polypeptides. A general role of NME in modulating the half-life of key subsets of proteins is suggested.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available