Dataset Information

Proteomic data of MG132 treated A. thaliana WT and ppi2

ABSTRACT: A mutation in the proteasomal lid subunit Rpn8a alters proteasome composition and exerts a beneficial effect on photosynthesis. The effect is particularly visible in a double mutant between rpn8a and the plastid protein import receptor Toc159 (ppi2xrpn8a) but also in an rpn8a single mutant that shows higher PSII efficiency and lower non-photochemical quenching. The double mutant shows elevated accumulation of pigments, higher levels of thylakoid membrane proteins and higher PSII quantum yield compared to the ppi2 single mutant. While proplastid-like pro-thylakoid structures are characteristic for ppi2, stacked thylakoids are frequently observed in the double mutant. The rpn8a mutation is accompanied by higher 20S and lower 26S proteasome abundance and increased expression levels of proteolytic stress markers. Unlike known retrograde signaling chains, there is no effect on the transcription of selected photosynthesis associated nuclear encoded gens (PhanGs). Since plastid precursor protein abundance is elevated in the double mutant it is conceivable that the changes in proteasome composition affect precursor stability. We propose a model in which mild proteasome impairment shifts the equilibrium between precursor import and degradation towards import, which is especially effective in plastid protein import mutants but also detectable in the wildtype background, albeit to a much weaker extent.

INSTRUMENT(S): Synapt MS

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

TISSUE(S): Plant Cell, Root, Leaf, Rosette, Shoot

SUBMITTER: Sacha Baginsky

LAB HEAD: Sacha Baginsky

PROVIDER: PXD014560 | Pride | 2020-05-27

REPOSITORIES: Pride

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Dataset's files

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			Action	DRS
	JGR_20170403_col_DMSO_biorep1_001.raw.zip	Raw
	JGR_20170403_col_DMSO_biorep1_001.zip	Other
	JGR_20170403_col_DMSO_biorep1_002.raw.zip	Raw
	JGR_20170403_col_DMSO_biorep1_002.zip	Other
	JGR_20170403_col_DMSO_biorep1_003.raw.zip	Raw

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Publications

Mild proteasomal stress improves photosynthetic performance in Arabidopsis chloroplasts.

Grimmer Julia J Helm Stefan S Dobritzsch Dirk D Hause Gerd G Shema Gerta G Zahedi René P RP Baginsky Sacha S

Nature communications 20200403 1

The proteasome is an essential protein-degradation machinery in eukaryotic cells that controls protein turnover and thereby the biogenesis and function of cell organelles. Chloroplasts import thousands of nuclear-encoded precursor proteins from the cytosol, suggesting that the bulk of plastid proteins is transiently exposed to the cytosolic proteasome complex. Therefore, there is a cytosolic equilibrium between chloroplast precursor protein import and proteasomal degradation. We show here that a ...[more]

PMID: 32245955

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