title: Cross-talk between calcium signalling and protein phosphorylation at the thylakoid.
abstract: The role of protein phosphorylation for adjusting chloroplast functions to changing environmental needs is well established, whereas calcium signalling in the chloroplast is only recently becoming appreciated. The work presented here explores the potential cross-talk between calcium signalling and protein phosphorylation in chloroplasts and provides the first evidence for targets of calcium-dependent protein phosphorylation at the thylakoid membrane. Thylakoid proteins were screened for calcium-dependent phosphorylation by 2D gel electrophoresis combined with phospho-specific labelling and PsaN, CAS, and VAR1, among other proteins, were identified repeatedly by mass spectrometry. Subsequently their calcium-dependent phosphorylation was confirmed in kinase assays using the purified proteins and chloroplast extracts. This is the first report on the protein targets of calcium-dependent phosphorylation of thylakoid proteins and provides ground for further studies in this direction.
authors.affiliation: Department of Biochemistry and Cell Biology, MFPL, University of Vienna, Dr. Bohrgasse 9, A-1030, Vienna, Austria.
authors.forename: Simon
authors.initials: S
authors.lastname: Stael
authors.forename: Agostinho G
authors.initials: AG
authors.lastname: Rocha
authors.forename: Terje
authors.initials: T
authors.lastname: Wimberger
authors.forename: Dorothea
authors.initials: D
authors.lastname: Anrather
authors.forename: Ute C
authors.initials: UC
authors.lastname: Vothknecht
authors.forename: Markus
authors.initials: M
authors.lastname: Teige
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D002736:Chloroplasts / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D018532:Pisum sativum / Q000378:metabolism; D010766:Phosphorylation; D010940:Plant Proteins / Q000378:metabolism*; D015398:Signal Transduction; D020524:Thylakoids / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D010940:Plant Proteins; D002118:Calcium