Complexome profiling of the Chlamydomonas <i>psb28</i> mutant reveals TEF5 as an early PSII assembly factor

PSII assembly requires auxiliary factors, including Psb28. Although the absence of Psb28 in cyanobacteria has little effect on PSII assembly, we show here that the Chlamydomonas (Chlamydomonas reinhardtii) psb28 null mutant is severely impaired in PSII assembly, showing drastically reduced PSII supercomplexes, dimers, and monomers, while overaccumulating early PSII assembly intermediates reaction center II (RCII), CP43mod, and D1mod. The mutant had less PSI and more cytochrome b6f complex, its thylakoids were organized mainly as monolayers, and it had a distorted chloroplast morphology. Complexome profiling of the psb28 mutant revealed that THYLAKOID ENRICHED FRACTION 5 (TEF5), the homolog of Arabidopsis (Arabidopsis thaliana) PHOTOSYSTEM B PROTEIN 33/LIGHT HARVESTING-LIKE 8, comigrated particularly with RCII. TEF5 also interacted with PSI. A Chlamydomonas tef5 null mutant was severely impaired in PSII assembly and overaccumulated RCII and CP43mod. RC47 was not detectable in the light-grown tef5 mutant. Our data suggest a possible role for TEF5 in RCII photoprotection or maturation. Both the psb28 and tef5 mutants exhibited decreased synthesis of CP47 and PsbH, suggesting negative feedback regulation possibly exerted by the accumulation of RCII and/or CP43mod in both mutants. The strong effects of missing auxiliary factors on PSII assembly in Chlamydomonas suggest a more effective protein quality control system in this alga than in land plants and cyanobacteria.

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Journal
The Plant Cell
Published
2025-03-17
DOI
https://doi.org/10.1093/plcell/koaf055
Citations
3
Primary Topic
Photosynthetic Processes and Mechanisms
Type
article
Field-Weighted Citation Impact
2.42

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article

Complexome profiling of the Chlamydomonas psb28 mutant reveals TEF5 as an early PSII assembly factor

Matthieu Mustas, Benedikt Venn, Till Rudack, Yves Choquet et al.
3 citations
The Plant Cell
Photosynthetic Processes and Mechanisms
2.42
article

Complexome profiling of the Chlamydomonas psb28 mutant reveals TEF5 as an early PSII assembly factor

Matthieu Mustas, Benedikt Venn, Till Rudack, Yves Choquet, Frederik Sommer, Benjamin Spaniol, Pawel Brzezowski, Katharina König, Jure Zabret, David Scheuring, Matthias Ostermeier, Michael Schroda, Stefan Geimer, Torben Fürtges, Françis-André Wollman, Timo Mühlhaus, Saskia Zeilfelder, Lara Spaniol, Julia Lang, Marc M Nowacyzk
article en
3 citations

Abstract

PSII assembly requires auxiliary factors, including Psb28. Although the absence of Psb28 in cyanobacteria has little effect on PSII assembly, we show here that the Chlamydomonas (Chlamydomonas reinhardtii) psb28 null mutant is severely impaired in PSII assembly, showing drastically reduced PSII supercomplexes, dimers, and monomers, while overaccumulating early PSII assembly intermediates reaction center II (RCII), CP43mod, and D1mod. The mutant had less PSI and more cytochrome b6f complex, its thylakoids were organized mainly as monolayers, and it had a distorted chloroplast morphology. Complexome profiling of the psb28 mutant revealed that THYLAKOID ENRICHED FRACTION 5 (TEF5), the homolog of Arabidopsis (Arabidopsis thaliana) PHOTOSYSTEM B PROTEIN 33/LIGHT HARVESTING-LIKE 8, comigrated particularly with RCII. TEF5 also interacted with PSI. A Chlamydomonas tef5 null mutant was severely impaired in PSII assembly and overaccumulated RCII and CP43mod. RC47 was not detectable in the light-grown tef5 mutant. Our data suggest a possible role for TEF5 in RCII photoprotection or maturation. Both the psb28 and tef5 mutants exhibited decreased synthesis of CP47 and PsbH, suggesting negative feedback regulation possibly exerted by the accumulation of RCII and/or CP43mod in both mutants. The strong effects of missing auxiliary factors on PSII assembly in Chlamydomonas suggest a more effective protein quality control system in this alga than in land plants and cyanobacteria.

The Plant CellVol. 37(6)
Jagiellonian University (PL), Centre National de la Recherche Scientifique (FR), University of Kaiserslautern (DE), Sorbonne Université (FR), Biologie du chloroplaste et perception de la lumière chez les micro-algues (FR), Institut de Biologie Physico-Chimique (FR), Biologie du Chloroplaste et Perception de la Lumière chez les Microalgues (FR), University of Rostock (DE), University of Bayreuth (DE), University of Regensburg (DE), University of Applied Sciences Kaiserslautern (DE), Ludwig-Maximilians-Universität München (DE), Ruhr University Bochum (DE)
Deutsche Forschungsgemeinschaft
Life in Land
Openalex Percentile: Top 13%
Photosynthetic Processes and Mechanisms
2.42
DOIOpen Access PDFOpenAlex
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