title: PHOTOSYSTEM II SUBUNIT R is required for efficient binding of LIGHT-HARVESTING COMPLEX STRESS-RELATED PROTEIN3 to photosystem II-light-harvesting supercomplexes in Chlamydomonas reinhardtii.
abstract: In Chlamydomonas reinhardtii, the LIGHT-HARVESTING COMPLEX STRESS-RELATED PROTEIN3 (LHCSR3) protein is crucial for efficient energy-dependent thermal dissipation of excess absorbed light energy and functionally associates with photosystem II-light-harvesting complex II (PSII-LHCII) supercomplexes. Currently, it is unknown how LHCSR3 binds to the PSII-LHCII supercomplex. In this study, we investigated the role of PHOTOSYSTEM II SUBUNIT R (PSBR) an intrinsic membrane-spanning PSII subunit, in the binding of LHCSR3 to PSII-LHCII supercomplexes. Down-regulation of PSBR expression diminished the efficiency of oxygen evolution and the extent of nonphotochemical quenching and had an impact on the stability of the oxygen-evolving complex as well as on PSII-LHCII-LHCSR3 supercomplex formation. Its down-regulation destabilized the PSII-LHCII supercomplex and strongly reduced the binding of LHCSR3 to PSII-LHCII supercomplexes, as revealed by quantitative proteomics. PHOTOSYSTEM II SUBUNIT P deletion, on the contrary, destabilized PHOTOSYSTEM II SUBUNIT Q binding but did not affect PSBR and LHCSR3 association with PSII-LHCII. In summary, these data provide clear evidence that PSBR is required for the stable binding of LHCSR3 to PSII-LHCII supercomplexes and is essential for efficient energy-dependent quenching and the integrity of the PSII-LHCII-LHCSR3 supercomplex under continuous high light.
authors.affiliation: Institute of Plant Biology and Biotechnology, University of Münster, 48143 Muenster, Germany (H.X., S.V.B., M.S., M.H.); andDivision of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan (R.T., J.M.).
authors.forename: Huidan
authors.initials: H
authors.lastname: Xue
authors.affiliation: Institute of Plant Biology and Biotechnology, University of Münster, 48143 Muenster, Germany (H.X., S.V.B., M.S., M.H.); andDivision of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan (R.T., J.M.).
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Tokutsu
authors.affiliation: Institute of Plant Biology and Biotechnology, University of Münster, 48143 Muenster, Germany (H.X., S.V.B., M.S., M.H.); andDivision of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan (R.T., J.M.).
authors.forename: Sonja Verena
authors.initials: SV
authors.lastname: Bergner
authors.affiliation: Institute of Plant Biology and Biotechnology, University of Münster, 48143 Muenster, Germany (H.X., S.V.B., M.S., M.H.); andDivision of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan (R.T., J.M.).
authors.forename: Martin
authors.initials: M
authors.lastname: Scholz
authors.affiliation: Institute of Plant Biology and Biotechnology, University of Münster, 48143 Muenster, Germany (H.X., S.V.B., M.S., M.H.); andDivision of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan (R.T., J.M.).
authors.forename: Jun
authors.initials: J
authors.lastname: Minagawa
authors.affiliation: Institute of Plant Biology and Biotechnology, University of Münster, 48143 Muenster, Germany (H.X., S.V.B., M.S., M.H.); andDivision of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan (R.T., J.M.) mhippler@uni-muenster.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Hippler
mesh_terms: D000595:Amino Acid Sequence; D016825:Chlamydomonas reinhardtii / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects; D002734:Chlorophyll / Q000378:metabolism; D015536:Down-Regulation; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010100:Oxygen / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D011485:Protein Binding; D040901:Proteomics; D016415:Sequence Alignment; D020524:Thylakoids / Q000378:metabolism
chemical_list: D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D010100:Oxygen