Phosphomimicking within the transit peptide of pHCF136 leads to reduced photosystem II accumulation in vivo.
Most chloroplast resident proteins are equipped with N-terminal transit peptides to ensure targeting from the cytosol to the organelle. Import rates can be modulated by phosphorylation and 14-3-3 binding within the transit peptides. Using the phosphorylatable preprotein pHCF136, a photosystem II assembly factor, we investigated the function of preprotein phosphorylation in vivo by complementing the seedling lethal hcf136 mutant. HCF136 constructs containing mutations within the 14-3-3 binding site were generated, either abolishing or mimicking phosphorylation. Interestingly, phosphomimicking reduced the import rate and the hcf136 phenotype could only be partially rescued, as shown by hampered photosystem II complex accumulation, which was most prominently observed in cotyledons.
Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse 2-4, 82152 Planegg-Martinsried, Germany.
Catharina
C
Nickel
Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse 2-4, 82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany.
Jürgen
J
Soll
Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse 2-4, 82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany. Electronic address: serena.schwenkert@lmu.de.
Serena
S
Schwenkert
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002736:Chloroplasts / Q000201:enzymology / Q000378:metabolism*; D018548:Cotyledon / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D005816:Genetic Complementation Test; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D018716:Molecular Mimicry; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D021382:Protein Sorting Signals; D055550:Protein Stability; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism
D029681:Arabidopsis Proteins; C115034:HCF136 protein, Arabidopsis; D008565:Membrane Proteins; D010446:Peptide Fragments; D045332:Photosystem II Protein Complex; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins
Arabidopsis thaliana; Chloroplast; HCF136; Phosphorylation; Photosystem II; Protein import