scholarly journals The Small Ubiquitin-like Modifier (SUMO) Protein Modification System inArabidopsis

2002 ◽  
Vol 278 (9) ◽  
pp. 6862-6872 ◽  
Author(s):  
Jasmina Kurepa ◽  
Joseph M. Walker ◽  
Jan Smalle ◽  
Mark M. Gosink ◽  
Seth J. Davis ◽  
...  
Keyword(s):  
Protein Modification ◽  
Modification System ◽  
Sumo Protein

N-glycosylation of the CmeABC multidrug efflux pump is needed for optimal function in Campylobacter jejuni

Glycobiology ◽  
2019 ◽  
Vol 30 (2) ◽  
pp. 105-119 ◽  
Author(s):  
Rajinder K Dubb ◽  
Harald Nothaft ◽  
Bernadette Beadle ◽  
Michele R Richards ◽  
Christine M Szymanski
Keyword(s):  
Campylobacter Jejuni ◽  
Protein Modification ◽  
Efflux Pump ◽  
Protein Structures ◽  
Protein Glycosylation ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Modification System ◽  
Glycosylation Pathway

Abstract Campylobacter jejuni is a prevalent gastrointestinal pathogen associated with increasing rates of antimicrobial resistance development. It was also the first bacterium demonstrated to possess a general N-linked protein glycosylation pathway capable of modifying > 80 different proteins, including the primary Campylobacter multidrug efflux pump, CmeABC. Here we demonstrate that N-glycosylation is necessary for the function of the efflux pump and may, in part, explain the evolutionary pressure to maintain this protein modification system. Mutants of cmeA in two common wildtype (WT) strains are highly susceptible to erythromycin (EM), ciprofloxacin and bile salts when compared to the isogenic parental strains. Complementation of the cmeA mutants with the native cmeA allele restores the WT phenotype, whereas expression of a cmeA allele with point mutations in both N-glycosylation sites is comparable to the cmeA mutants. Moreover, loss of CmeA glycosylation leads to reduced chicken colonization levels similar to the cmeA knock-out strain, while complementation fully restores colonization. Reconstitution of C. jejuni CmeABC into Escherichia coli together with the C. jejuni N-glycosylation pathway increases the EM minimum inhibitory concentration and decreases ethidium bromide accumulation when compared to cells lacking the pathway. Molecular dynamics simulations reveal that the protein structures of the glycosylated and non-glycosylated CmeA models do not vary from one another, and in vitro studies show no change in CmeA multimerization or peptidoglycan association. Therefore, we conclude that N-glycosylation has a broader influence on CmeABC function most likely playing a role in complex stability.

scholarly journals Apg7p/Cvt2p Is Required for the Cytoplasm-to-Vacuole Targeting, Macroautophagy, and Peroxisome Degradation Pathways

1999 ◽  
Vol 10 (5) ◽  
pp. 1337-1351 ◽  
Author(s):  
John Kim ◽  
Valerie M. Dalton ◽  
Kimberly P. Eggerton ◽  
Sidney V. Scott ◽  
Daniel J. Klionsky
Keyword(s):  
Protein Modification ◽  
Protein Targeting ◽  
Fluorescent Protein ◽  
Molecular Genetic ◽  
Subcellular Fractionation ◽  
Dependent Manner ◽  
Conjugation System ◽  
Modification System ◽  
Green Fluorescent ◽  
Starvation Conditions

Proper functioning of organelles necessitates efficient protein targeting to the appropriate subcellular locations. For example, degradation in the fungal vacuole relies on an array of targeting mechanisms for both resident hydrolases and their substrates. The particular processes that are used vary depending on the available nutrients. Under starvation conditions, macroautophagy is the primary method by which bulk cytosol is sequestered into autophagic vesicles (autophagosomes) destined for this organelle. Molecular genetic, morphological, and biochemical evidence indicates that macroautophagy shares much of the same cellular machinery as a biosynthetic pathway for the delivery of the vacuolar hydrolase, aminopeptidase I, via the cytoplasm-to-vacuole targeting (Cvt) pathway. The machinery required in both pathways includes a novel protein modification system involving the conjugation of two autophagy proteins, Apg12p and Apg5p. The conjugation reaction was demonstrated to be dependent on Apg7p, which shares homology with the E1 family of ubiquitin-activating enzymes. In this study, we demonstrate that Apg7p functions at the sequestration step in the formation of Cvt vesicles and autophagosomes. The subcellular localization of Apg7p fused to green fluorescent protein (GFP) indicates that a subpopulation of Apg7pGFP becomes membrane associated in an Apg12p-dependent manner. Subcellular fractionation experiments also indicate that a portion of the Apg7p pool is pelletable under starvation conditions. Finally, we demonstrate that the Pichia pastoris homologue Gsa7p that is required for peroxisome degradation is functionally similar to Apg7p, indicating that this novel conjugation system may represent a general nonclassical targeting mechanism that is conserved across species.

Developmental regulation of Ubc9 in the rat nervous system.

2008 ◽  
Vol 55 (4) ◽  
pp. 681-686 ◽  
Author(s):  
Mutsufusa Watanabe ◽  
Kaoru Takahashi ◽  
Kayoko Tomizawa ◽  
Hidehiro Mizusawa ◽  
Hiroshi Takahashi
Keyword(s):  
Protein Modification ◽  
Pyramidal Neurons ◽  
Hippocampal Formation ◽  
Developmental Regulation ◽  
Covalent Modification ◽  
Adult Brain ◽  
Modification System ◽  
Neuronal Stem Cells ◽  
Protein Levels ◽  
Conjugating Enzyme

The SUMO-conjugating enzyme Ubc9 is an essential enzyme in the SUMO (small ubiquitin-related modifier) protein modification system. Although sumoylation, covalent modification of cellular proteins by SUMO, is considered to regulate various cellular processes, and many substrates for sumoylation have been identified recently, the regulation of Ubc9 expression has not been examined in detail. We analyzed the expression of Ubc9 during rat brain development at the mRNA and protein levels. Northern and Western blot analyses revealed that expression of Ubc9 and SUMO-1 was developmentally regulated, while that of the ubiquitin-conjugating enzyme UbcH7 did not change so dramatically. In situ hybridization analysis revealed that the expression of Ubc9 was high in neuronal stem cells and moderate in differentiated neurons at embryonic stages. In the adult brain, moderate expression was observed in subsets of neurons, such as the dentate granular neurons and pyramidal neurons in the hippocampal formation and the large pyramidal neurons in the cerebral cortex. These results suggest that the Ubc9-SUMO system might participate in the proliferation and differentiation of neuronal cells in the developing brain and in neuronal plasticity in the adult brain.

scholarly journals Protein Modification System in Dormant Cells

2009 ◽  
Vol 129 (10) ◽  
pp. 1221-1225 ◽  
Author(s):  
Ritsuko KUWANA
Keyword(s):  
Protein Modification ◽  
Modification System ◽  
Dormant Cells

Unrestrictive protein modification localization and quality control for open search of mass spectra

2018 ◽  
Author(s):  
Zhiwu An ◽  
Fuzhou Gong ◽  
Yan Fu
Keyword(s):  
Mass Spectrometry ◽  
Quality Control ◽  
Tandem Mass Spectrometry ◽  
Mass Spectra ◽  
Protein Modification ◽  
Software Tool ◽  
Tandem Mass ◽  
Simulation Data ◽  
Post Translational Modifications

We have developed PTMiner, a first software tool for automated, confident filtering, localization and annotation of protein post-translational modifications identified by open (mass-tolerant) search of large tandem mass spectrometry datasets. The performance of the software was validated on carefully designed simulation data. <br>

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