Abstract
The membrane protease LonB is an essential protein in the archaeon Haloferax volcanii and globally impacts its physiology. However, natural substrates of the archaeal Lon protease have not been identified. The whole proteome turnover was examined in a H. volcanii LonB mutant under reduced and physiological protease levels. LC–MS/MS combined with stable isotope labeling was applied for the identification/quantitation of membrane and cytoplasm proteins. Differential synthesis and degradation rates were evidenced for 414 proteins in response to Lon expression. A total of 58 proteins involved in diverse cellular processes showed a degradation pattern (none/very little degradation in the absence of Lon and increased degradation in the presence of Lon) consistent with a LonB substrate, which was further substantiated for several of these candidates by pull-down assays. The most notable was phytoene synthase (PSY), the rate-limiting enzyme in carotenoid biosynthesis. The rapid degradation of PSY upon LonB induction in addition to the remarkable stabilization of this protein and hyperpigmentation phenotype in the Lon mutant strongly suggest that PSY is a LonB substrate. This work identifies for the first time candidate targets of the archaeal Lon protease and establishes proteolysis by Lon as a novel post-translational regulatory mechanism of carotenogenesis.
DOI
10.1021/acs.jproteome.7b00809
Publication Date
2018-03-02
Publication Title
Journal of Proteome Research
Volume
17
Issue
3
Publisher
American Chemical Society
ISSN
1535-3907
Embargo Period
2024-11-19
First Page
1158
Last Page
1171
Recommended Citation
Cerletti, M., Paggi, R., Troetschel, C., Ferrari, M., & et al. (2018) 'LonB Protease Is a Novel Regulator of Carotenogenesis Controlling Degradation of Phytoene Synthase in Haloferax volcanii', Journal of Proteome Research, 17(3), pp. 1158-1171. American Chemical Society: Available at: https://doi.org/10.1021/acs.jproteome.7b00809
