Global regulation via modulation of ribosome pausing by the ABC-F protein EttA.

Having multiple rounds of translation of the same mRNA creates dynamic complexities along with opportunities for regulation related to ribosome pausing and stalling at specific sequences. Yet, mechanisms controlling these critical processes and the principles guiding their evolution remain poorly understood. Through genetic, genomic, physiological, and biochemical approaches, we demonstrate that regulating ribosome pausing at specific amino acid sequences can produce ~2-fold changes in protein expression levels which strongly influence cell growth and therefore evolutionary fitness.

New RoxS sRNA Targets Identified in Bacillus subtilis by Pulsed SILAC.

Non-coding RNAs (sRNA) play a key role in controlling gene expression in bacteria, typically by base-pairing with ribosome binding sites to block translation. The modification of ribosome traffic along the mRNA generally affects its stability. However, a few cases have been described in bacteria where sRNAs can affect translation without a major impact on mRNA stability.

Extending the Range of SLIM-Labeling Applications: From Human Cell Lines in Culture to Whole-Organism Labeling.

The simple light isotope metabolic-labeling technique relies on the biosynthesis of amino acids from U-[C]-labeled molecules provided as the sole carbon source. The incorporation of the resulting U-[C]-amino acids into proteins presents several key advantages for mass-spectrometry-based proteomics analysis, as it results in more intense monoisotopic ions, with a better signal-to-noise ratio in bottom-up analysis. In our initial studies, we developed the simple light isotope metabolic (SLIM)-labeling strategy using prototrophic eukaryotic microorganisms, the yeasts and , as well as strains with genetic markers that lead to amino-acid auxotrophy.

The Polo kinase Cdc5 is regulated at multiple levels in the adaptation response to telomere dysfunction.

Telomere dysfunction activates the DNA damage checkpoint to induce a cell cycle arrest. After an extended period of time, however, cells can bypass the arrest and undergo cell division despite the persistence of the initial damage, a process called adaptation to DNA damage. The Polo kinase Cdc5 in Saccharomyces cerevisiae is essential for adaptation and for many other cell cycle processes.

The C-Terminal Acidic Tail Modulates the Anticancer Properties of HMGB1.

Energy metabolism reprogramming was recently listed as a hallmark of cancer. In this process, the switch from pyruvate kinase isoenzyme type M1 to pyruvate kinase isoenzyme type M2 (PKM2) is believed to play a crucial role. Interestingly, the activity of the active form of PKM2 can efficiently be inhibited by the high-mobility group box 1 (HMGB1) protein, leading to a rapid blockage of glucose-dependent aerobic respiration and cancer cell death.

Properties of Photosystem II lacking the PsbJ subunit.

Photosystem II (PSII), the oxygen-evolving enzyme, consists of 17 trans-membrane and 3 extrinsic membrane proteins. Other subunits bind to PSII during assembly, like Psb27, Psb28, and Tsl0063. The presence of Psb27 has been proposed (Zabret et al.

The labile interactions of cyclic electron flow effector proteins.

The supramolecular organization of membrane proteins (MPs) is sensitive to environmental changes in photosynthetic organisms. Isolation of MP supercomplexes from the green algae , which are believed to contribute to cyclic electron flow (CEF) between the cytochrome complex (Cyt-) and photosystem I (PSI), proved difficult. We were unable to isolate a supercomplex containing both Cyt- and PSI because in our hands, most of Cyt- did not comigrate in sucrose density gradients, even upon using chemical cross-linkers or amphipol substitution of detergents.

The Deep Thioredoxome in Chlamydomonas reinhardtii: New Insights into Redox Regulation.

Thiol-based redox post-translational modifications have emerged as important mechanisms of signaling and regulation in all organisms, and thioredoxin plays a key role by controlling the thiol-disulfide status of target proteins. Recent redox proteomic studies revealed hundreds of proteins regulated by glutathionylation and nitrosylation in the unicellular green alga Chlamydomonas reinhardtii, while much less is known about the thioredoxin interactome in this organism. By combining qualitative and quantitative proteomic analyses, we have comprehensively investigated the Chlamydomonas thioredoxome and 1188 targets have been identified.