title: Protein import-independent functions of Tic56, a component of the 1-MDa translocase at the inner chloroplast envelope membrane.
abstract: Tic56 is an essential subunit of a 1-MDa protein complex at the inner chloroplast envelope membrane that comprises Tic100, Tic214 and the protein conducting channel protein Tic20-I. The complex was characterized as the "general protein import translocase" because mutants in either of its subunits have a severe growth phenotype and fail to assemble a photosynthetic machinery. In a recent publication we show that the albino phenotype of tic56-1 mutants results at least in part from a defect in ribosome assembly and a deficiency in plastid translation. We furthermore could not detect any impairment of protein import activity with plastids from tic56-3 mutants, despite a lack of full-length Tic56 and a decreased abundance of other 1-MDa complex subunits. These findings suggest that the 1-MDa complex consists of subunits that have functions other than protein import.
authors.affiliation: a Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg , Biozentrum, Weinbergweg, Halle (Saale) , Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Agne
authors.affiliation: a Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg , Biozentrum, Weinbergweg, Halle (Saale) , Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Köhler
authors.affiliation: a Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg , Biozentrum, Weinbergweg, Halle (Saale) , Germany.
authors.forename: Sacha
authors.initials: S
authors.lastname: Baginsky
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D040901:Proteomics
chemical_list: D029681:Arabidopsis Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D010940:Plant Proteins; C000604211:Tic56 protein, Arabidopsis
keywords: Chloroplast; protein import; quantitative proteomics; translocon at the inner chloroplast envelope membrane