Effect of precursor protein phosphorylation on import into isolated chloroplasts from Chlamydomonas.
In higher plants, chloroplast-destined precursor proteins are thought to be phosphorylated. Mediated by a specific 14-3-3 protein, these phosphorylated proteins bind to the chloroplast surface and are subsequently imported into the chloroplast. We demonstrate that also in the green alga Chlamydomonas reinhardtii the precursor of the small subunit of ribulose-1,5-bisphosphate carboxylase becomes phosphorylated by a plant protein kinase and that the phosphorylation site is located in the transit peptide. The phosphorylation status of the precursor protein regulates its import into chloroplasts especially at an early step during this process. The possible physiological function is discussed.
Su
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Q
Department of Chemistry and Biochemistry, University of Bern, Switzerland. qingxiang.su@ipw.biol.ethz.ch
Schmid
K
K
Schild
C
C
Boschetti
A
A
D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000187:drug effects / Q000378:metabolism*; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D004791:Enzyme Inhibitors / Q000494:pharmacology; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010940:Plant Proteins / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D011498:Protein Precursors / Q000737:chemistry / Q000378:metabolism*; D021382:Protein Sorting Signals / Q000502:physiology; D021122:Protein Subunits; D021381:Protein Transport / Q000187:drug effects; D012273:Ribulose-Bisphosphate Carboxylase / Q000737:chemistry / Q000378:metabolism*
D004791:Enzyme Inhibitors; D010940:Plant Proteins; D011498:Protein Precursors; D021382:Protein Sorting Signals; D021122:Protein Subunits; D011494:Protein Kinases; D010744:Phosphoric Monoester Hydrolases; D012273:Ribulose-Bisphosphate Carboxylase