title: HCF243 encodes a chloroplast-localized protein involved in the D1 protein stability of the arabidopsis photosystem II complex.
abstract: Numerous auxiliary nuclear factors have been identified to be involved in the dynamics of the photosystem II (PSII) complex. In this study, we characterized the high chlorophyll fluorescence243 (hcf243) mutant of Arabidopsis (Arabidopsis thaliana), which shows higher chlorophyll fluorescence and is severely deficient in the accumulation of PSII supercomplexes compared with the wild type. The amount of core subunits was greatly decreased, while the outer antenna subunits and other subunits were hardly affected in hcf243. In vivo protein-labeling experiments indicated that the synthesis rate of both D1 and D2 proteins decreased severely in hcf243, whereas no change was found in the rate of other plastid-encoded proteins. Furthermore, the degradation rate of the PSII core subunit D1 protein is higher in hcf243 than in the wild type, and the assembly of PSII is retarded significantly in the hcf243 mutant. HCF243, a nuclear gene, encodes a chloroplast protein that interacts with the D1 protein. HCF243 homologs were identified in angiosperms with one or two copies but were not found in lower plants and prokaryotes. These results suggest that HCF243, which arose after the origin of the higher plants, may act as a cofactor to maintain the stability of D1 protein and to promote the subsequent assembly of the PSII complex.
authors.affiliation: Molecular Ecology Group, State Key Laboratory of Grassland Farming System, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China.
authors.forename: Dongyuan
authors.initials: D
authors.lastname: Zhang
authors.forename: Gongke
authors.initials: G
authors.lastname: Zhou
authors.forename: Bingbing
authors.initials: B
authors.lastname: Liu
authors.forename: Yingzhen
authors.initials: Y
authors.lastname: Kong
authors.forename: Na
authors.initials: N
authors.lastname: Chen
authors.forename: Qiang
authors.initials: Q
authors.lastname: Qiu
authors.forename: Hongju
authors.initials: H
authors.lastname: Yin
authors.forename: Jiaxing
authors.initials: J
authors.lastname: An
authors.forename: Fang
authors.initials: F
authors.lastname: Zhang
authors.forename: Fan
authors.initials: F
authors.lastname: Chen
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D060365:Chloroplast Proteins / Q000235:genetics / Q000378:metabolism*; D005453:Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D018087:Plastids / Q000235:genetics; D055550:Protein Stability; D012333:RNA, Messenger / Q000378:metabolism; D020524:Thylakoids / Q000737:chemistry
chemical_list: D029681:Arabidopsis Proteins; D060365:Chloroplast Proteins; C571111:HCF243 protein, Arabidopsis; D009687:Nuclear Proteins; D045332:Photosystem II Protein Complex; D012333:RNA, Messenger; D002734:Chlorophyll