Differential Roles of the Thylakoid Lumenal Deg Protease Homologs in Chloroplast Proteostasis
| Autor: | Albina Lin, Ziv Reich, Yana Butenko, Leah Naveh, Meital Kupervaser, Yishai Levin, Zach Adam |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Proteomics
0106 biological sciences 0301 basic medicine Proteases Photoinhibition Physiology medicine.medical_treatment Arabidopsis Plant Science Thylakoids 01 natural sciences Gene Knockout Techniques 03 medical and health sciences Gene Expression Regulation Plant Genetics medicine Arabidopsis thaliana Photosynthesis Protease biology Arabidopsis Proteins Chemistry Serine Endopeptidases Wild type Articles biology.organism_classification Cell biology Plant Leaves Phenotype 030104 developmental biology Proteostasis Seedlings Thylakoid Mutation 010606 plant biology & botany |
| Zdroj: | Plant Physiology. 178:1065-1080 |
| ISSN: | 1532-2548 0032-0889 |
| DOI: | 10.1104/pp.18.00912 |
| Popis: | Deg proteases are involved in protein quality control in prokaryotes. Of the three Arabidopsis (Arabidopsis thaliana) homologs, Deg1, Deg5, and Deg8, located in the thylakoid lumen, Deg1 forms a homohexamer, whereas Deg5 and Deg8 form a heterocomplex. Both Deg1 and Deg5-Deg8 were shown separately to degrade photosynthetic proteins during photoinhibition. To investigate whether Deg1 and Deg5-Deg8 are redundant, a full set of Arabidopsis Deg knockout mutants were generated and their phenotypes were compared. Under all conditions tested, deg1 mutants were affected more than the wild type and deg5 and deg8 mutants. Moreover, overexpression of Deg5-Deg8 could only partially compensate for the loss of Deg1. Comparative proteomics of deg1 mutants revealed moderate up-regulation of thylakoid proteins involved in photoprotection, assembly, repair, and housekeeping and down-regulation of those that form photosynthetic complexes. Quantification of protein levels in the wild type revealed that Deg1 was 2-fold more abundant than Deg5-Deg8. Moreover, recombinant Deg1 displayed higher in vitro proteolytic activity. Affinity enrichment assays revealed that Deg1 was precipitated with very few interacting proteins, whereas Deg5-Deg8 was associated with a number of thylakoid proteins, including D1, OECs, LHCBs, Cyt b(6)f, and NDH subunits, thus implying that Deg5-Deg8 is capable of binding substrates but is unable to degrade them efficiently. This work suggests that differences in protein abundance and proteolytic activity underlie the differential importance of Deg1 and Deg5-Deg8 protease complexes observed in vivo. |
| Databáze: | OpenAIRE |
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