Université de Neuchâtel

The novel chloroplast outer membrane kinase KOC1 is a required component of the plastid protein import machinery

Zufferey-Arias, Mónica Alexandra ; Kessler, Felix (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2017.

The chloroplast constitutes the site of photosynthesis and is an essential organelle in plant cells. An endosymbiotic event was at the origin of the chloroplast, an ancestral eukaryotic cell engulfing a photosynthetic cyanobacterium. During evolution, the majority of ancestral chloroplast genes were lost or transferred to the nucleus. The protein products of the successfully transferred genes are...

Université de Neuchâtel

The Novel Chloroplast Outer Membrane Kinase KOC1 Is a Required Component of the Plastid Protein Import Machinery

Zufferey, Mónica ; Montandon, Cyrille ; Douet, Véronique ; Demarsy, Emilie ; Agne, Birgit ; Baginsky, Sacha ; Kessler, Felix

In: Journal of biological chemistry, 2017, vol. 292, no. 17, p. 6952-6964

The biogenesis and maintenance of cell organelles such as mitochondria and chloroplasts require the import of many proteins from the cytosol, a process that is controlled by phosphorylation. In the case of chloroplasts, the import of hundreds of different proteins depends on translocons at the outer and inner chloroplast membrane (TOC and TIC, respectively) complexes. The essential protein TOC159...

Université de Neuchâtel

The Chloroplast Import Receptor Toc90 Partially Restores the Accumulation of Toc159 Client Proteins in the Arabidopsis thaliana ppi2 Mutant

Infanger, Sibylle ; Bischof, Sylvain ; Hiltbrunner, Andreas ; Agne, Birgit ; Baginsky, Sacha ; Kessler, Felix

In: Molecular Plant, 2011, vol. 4, no. 2, p. 252–263

Successful import of hundreds of nucleus-encoded proteins is essential for chloroplast biogenesis. The import of cytosolic precursor proteins relies on the Toc- (translocon at the outer chloroplast membrane) and Tic- (translocon at the inner chloroplast membrane) complexes. In Arabidopsis thaliana, precursor recognition is mainly mediated by outer membrane receptors belonging to two...

Université de Neuchâtel

Border control: selectivity of chloroplast protein import and regulation at the TOC-complex

Demarsy, Emilie ; Lakshmanan, Ashok M ; Kessler, Felix

In: Frontiers in Plant Science, 2014, vol. 5, p. 483

Plants have evolved complex and sophisticated molecular mechanisms to regulate their development and adapt to their surrounding environment. Particularly the development of their specific organelles, chloroplasts and other plastid-types, is finely tuned in accordance with the metabolic needs of the cell. The normal development and functioning of plastids require import of particular subsets...

Université de Neuchâtel

Identification and characterization of putative Toc159 interacting partners

Montandon, Cyrille ; Kessler, Felix (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2015.

The chloroplast is the distinctive organelle of land plants and other photosynthetic eukaryotes. It carries out a variety of metabolic process, but photosynthesis is its main task and this is reflected in its structures and protein composition. Chloroplasts evolved from an endosymbiosis between a photosynthetic cyanobacterium and an ancestral eukaryote. Reminiscent of this autonomous origin, the...

Université de Neuchâtel

A plant split-ubiquitin system and TAP-tagging to study in vivo protein interactions in the chloroplast protein import machinery

Rahim, Gwendoline ; Kessler, Félix (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2008 ; Th. 2079.

Most chloroplast proteins are synthesized as precursor proteins in the cytosol. The import of these precursor proteins is mediated by molecular complexes located at the outer and inner membrane of the chloroplast. These complexes are called Toc (translocon at the outer envelope membrane) and Tic (translocon at the inner envelope membrane) respectively. In Arabidopsis, the Toc complex...

Université de Neuchâtel

AtToc90, a New GTP-Binding Component of the Arabidopsis Chloroplast Protein Import Machinery

Hiltbrunner, Andreas ; Grünig, Kathrin ; Alvarez-Huerta, Mayte ; Infanger, Sibylle ; Bauer, Jörg ; Kessler, Felix

In: Plant Molecular Biology, 2004, vol. 54, p. 427 - 440

AtToc159 is a GTP-binding chloroplast protein import receptor. In vivo, atToc159 is required for massive accumulation of photosynthetic proteins during chloroplast biogenesis. Yet, in mutants lacking atToc159 photosynthetic proteins still accumulate, but at strongly reduced levels whereas non-photosynthetic proteins are imported normally: This suggests a role for the homologues of atToc159...