@article{WinckRianoPachonSommeretal.2012, author = {Winck, Flavia V. and Riano-Pachon, Diego M. and Sommer, Frederik and Rupprecht, Jens and M{\"u}ller-R{\"o}ber, Bernd}, title = {The nuclear proteome of the green alga Chlamydomonas reinhardtii}, series = {Proteomics}, volume = {12}, journal = {Proteomics}, number = {1}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {1615-9853}, doi = {10.1002/pmic.201000782}, pages = {95 -- 100}, year = {2012}, abstract = {Nuclear proteins play a central role in regulating gene expression. Their identification is important for understanding how the nuclear repertoire changes over time under different conditions. Nuclear proteins are often underrepresented in proteomic studies due to the frequently low abundance of proteins involved in regulatory processes. So far, only few studies describing the nuclear proteome of plant species have been published. Recently, the genome sequence of the unicellular green alga Chlamydomonas reinhardtii has been obtained and annotated, allowing the development of further detailed studies for this organism. However, a detailed description of its nuclear proteome has not been reported so far. Here, we present an analysis of the nuclear proteome of the sequenced Chlamydomonas strain cc503. Using LC-MS/MS, we identified 672 proteins from nuclei isolates with a maximum 1\% peptide spectrum false discovery rate. Besides well-known proteins (e.g. histones), transcription factors and other transcriptional regulators (e.g. tubby and HMG) were identified. The presence of protein motifs in nuclear proteins was investigated by computational tools, and specific over-represented protein motifs were identified. This study provides new insights into the complexity of the nuclear environment and reveals novel putative protein targets for further studies of nuclear mechanisms.}, language = {en} } @article{NordhuesSchoettlerUngeretal.2012, author = {Nordhues, Andre and Sch{\"o}ttler, Mark Aurel and Unger, Ann-Katrin and Geimer, Stefan and Sch{\"o}nfelder, Stephanie and Schmollinger, Stefan and Ruetgers, Mark and Finazzi, Giovanni and Soppa, Barbara and Sommer, Frederik and M{\"u}hlhaus, Timo and Roach, Thomas and Krieger-Liszkay, Anja and Lokstein, Heiko and Luis Crespo, Jose and Schroda, Michael}, title = {Evidence for a role of VIPP1 in the structural organization of the photosynthetic apparatus in chlamydomonas}, series = {The plant cell}, volume = {24}, journal = {The plant cell}, number = {2}, publisher = {American Society of Plant Physiologists}, address = {Rockville}, issn = {1040-4651}, doi = {10.1105/tpc.111.092692}, pages = {637 -- 659}, year = {2012}, abstract = {The vesicle-inducing protein in plastids (VIPP1) was suggested to play a role in thylakoid membrane formation via membrane vesicles. As this functional assignment is under debate, we investigated the function of VIPP1 in Chlamydomonas reinhardtii. Using immunofluorescence, we localized VIPP1 to distinct spots within the chloroplast. In VIPP1-RNA interference/artificial microRNA cells, we consistently observed aberrant, prolamellar body-like structures at the origin of multiple thylakoid membrane layers, which appear to coincide with the immunofluorescent VIPP1 spots and suggest a defect in thylakoid membrane biogenesis. Accordingly, using quantitative shotgun proteomics, we found that unstressed vipp1 mutant cells accumulate 14 to 20\% less photosystems, cytochrome b(6)f complex, and ATP synthase but 30\% more light-harvesting complex II than control cells, while complex assembly, thylakoid membrane ultrastructure, and bulk lipid composition appeared unaltered. Photosystems in vipp1 mutants are sensitive to high light, which coincides with a lowered midpoint potential of the Q(A)/Q(A)(-) redox couple and increased thermosensitivity of photosystem II (PSII), suggesting structural defects in PSII. Moreover, swollen thylakoids, despite reduced membrane energization, in vipp1 mutants grown on ammonium suggest defects in the supermolecular organization of thylakoid membrane complexes. Overall, our data suggest a role of VIPP1 in the biogenesis/assembly of thylakoid membrane core complexes, most likely by supplying structural lipids.}, language = {en} }