GreenCut protein CPLD49 of Chlamydomonas reinhardtii associates with thylakoid membranes and is required for cytochrome b6f complex accumulation |
| |
| Authors: | Tyler M. Wittkopp Shai Saroussi Wenqiang Yang Xenie Johnson Rick G. Kim Mark L. Heinnickel James J. Russell Witchukorn Phuthong Rachel M. Dent Corey D. Broeckling Graham Peers Martin Lohr Francis‐André Wollman Krishna K. Niyogi Arthur R. Grossman |
| |
| Affiliation: | 1. Department of Biology, Stanford University, Stanford, CA, 94305 USA;2. Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305 USA;3. Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, Saint Paul lez Durance, France;4. Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305 USA;5. Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, CA, 94720‐3102 USA;6. Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 USA;7. Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, CO, 80523 USA;8. Department of Biology, Colorado State University, Fort Collins, CO, 80523 USA;9. Institut für Molekulare Physiologie – Pflanzenbiochemie, Johannes Gutenberg‐Universit?t, 55099 Mainz, Germany;10. Institut de Biologie Physico‐Chimique, CNRS‐UPMC, Paris, France;11. Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305 USAFor correspondence (e‐mail ). |
| |
| Abstract: | The GreenCut encompasses a suite of nucleus‐encoded proteins with orthologs among green lineage organisms (plants, green algae), but that are absent or poorly conserved in non‐photosynthetic/heterotrophic organisms. In Chlamydomonas reinhardtii, CPLD49 (C onserved in P lant L ineage and D iatoms49 ) is an uncharacterized GreenCut protein that is critical for maintaining normal photosynthetic function. We demonstrate that a cpld49 mutant has impaired photoautotrophic growth under high‐light conditions. The mutant exhibits a nearly 90% reduction in the level of the cytochrome b6f complex (Cytb6f), which impacts linear and cyclic electron transport, but does not compromise the ability of the strain to perform state transitions. Furthermore, CPLD49 strongly associates with thylakoid membranes where it may be part of a membrane protein complex with another GreenCut protein, CPLD38; a mutant null for CPLD38 also impacts Cytb6f complex accumulation. We investigated several potential functions of CPLD49, with some suggested by protein homology. Our findings are congruent with the hypothesis that CPLD38 and CPLD49 are part of a novel thylakoid membrane complex that primarily modulates accumulation, but also impacts the activity of the Cytb6f complex. Based on motifs of CPLD49 and the activities of other CPLD49‐like proteins, we suggest a role for this putative dehydrogenase in the synthesis of a lipophilic thylakoid membrane molecule or cofactor that influences the assembly and activity of Cytb6f. |
| |
| Keywords: | GreenCut photosynthesis cytochrome b6f electron transport chloroplast thylakoid membranes CPLD38 dehydrogenase |
|
|
