The prokaryotic N‐degron pathway depends on the Clp chaperone‐protease system and the ClpS adaptor for recognition of N‐degron bearing substrates. Plant chloroplasts contain a diversified Clp protease, including the ClpS homolog ClpS1. Several candidate ClpS1 substrates have been identified, but the N‐degron specificity is unclear. Here, we employed
A network of peptidases governs proteostasis in plant chloroplasts and mitochondria. This study reveals strong genetic and functional interactions in Arabidopsis between the chloroplast stromal CLP chaperone‐protease system and the PREP1,2 peptidases, which are dually localized to chloroplast stroma and the mitochondrial matrix. Higher order mutants defective in CLP or PREP proteins were generated and analyzed by quantitative proteomics and N‐terminal proteomics (terminal amine isotopic labeling of substrates (TAILS)). Strong synergistic interactions were observed between the CLP protease system ( Loss of chloroplast protease capacity interferes with stromal processing peptidase (SPP) activity due to folding stress and low levels of accumulated cleaved cTP fragments. PREP1,2 proteolysis of cleaved cTPs is complemented by unknown proteases. A model for CLP and PREP activity within a hierarchical chloroplast proteolysis network is proposed.
- Award ID(s):
- 1940961
- NSF-PAR ID:
- 10392915
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 236
- Issue:
- 4
- ISSN:
- 0028-646X
- Page Range / eLocation ID:
- p. 1339-1357
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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