Light regulation of CaS, a novel phosphoprotein in the thylakoid membrane of Arabidopsis thaliana.
Exposure of Arabidopsis thaliana plants to high levels of light revealed specific phosphorylation of a 40 kDa protein in photosynthetic thylakoid membranes. The protein was identified by MS as extracellular calcium-sensing receptor (CaS), previously reported to be located in the plasma membrane. By confocal laser scanning microscopy and subcellular fractionation, it was demonstrated that CaS localizes to the chloroplasts and is enriched in stroma thylakoids. The phosphorylation level of CaS responded strongly to light intensity. The light-dependent thylakoid protein kinase STN8 is required for CaS phosphorylation. The phosphorylation site was mapped to the stroma-exposed Thr380, located in a motif for interaction with 14-3-3 proteins and proteins with forkhead-associated domains, which suggests the involvement of CaS in stress responses and signaling pathways. The knockout Arabidopsis lines revealed a significant role for CaS in plant growth and development.
Vainonen
Julia P
JP
Department of Biology, Plant Physiology and Molecular Biology, University of Turku, Finland.
Sakuragi
Yumiko
Y
Stael
Simon
S
Tikkanen
Mikko
M
Allahverdiyeva
Yagut
Y
Paakkarinen
Virpi
V
Aro
Eveliina
E
Suorsa
Marjaana
M
Scheller
Henrik V
HV
Vener
Alexander V
AV
Aro
Eva-Mari
EM
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008027:Light; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D044169:Receptors, Calcium-Sensing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D020524:Thylakoids / Q000378:metabolism*
D010750:Phosphoproteins; D044169:Receptors, Calcium-Sensing; D011494:Protein Kinases; C504925:STN8 protein, Arabidopsis