Post-translational modifications effects

Proteosomal degration is the process by which improperly folded proteins or proteins with altered post-translational modifications are removed from a cell before they have a detrimental effect on cellular function. This is performed in small organelles known as proteosomes. Proteins are targeted for destruction in the proteosome by having a number of small ubiquitin molecules added. 

Graves DJ, Martin BL, WangJH Co-and Post-translational Modification ofiProteins Chemical Principles and Biological Effects. Oxford Univ Press, 1994. 

Proteomics, the measurement of the global changes in proteins produced as a result of gene expression, bridges the gap between genome sequence and cellular behaviour and takes into account the post-translational modifications that often result in the functional effect. It has the potential to determine the role of protein-protein complexes in the complex signalling cascades that... 

An example of the general approach is provided by a study of post-translational modification of the receptor for the peptide hormone, endothelin (Roos et al., 1998). Endothelin, a 21-amino acid peptide, is the strongest vasoconstrictor known it elicits physiological effects on cellular... 

Other target sites for certain pyrethroids include the voltage-gated calcium and chloride channels. Of particular interest is the increased effect of Type II pyrethroids on certain phosphoforms of the N-type Cav2.2 calcium channel following post-translational modification and its relationship to enhanced neurotransmitter release seen in vivo. 

Expression analysis using DNA microarrays analyzes only the transcriptome it should be mentioned that mRNA abundance in a cell often correlates poorly with the amount of protein synthesized (27). Important regulation takes place at the levels of translation and enzymatic activities. The only effect of a signal transduction pathway that is observed in a gene expression experiment is that at the endpoint of a given pathway. DNA microarrays currently have little value in determining post-translational modifications, which influence the diversity, affinity, function, cellular abundance, and transport of proteins. 

Although the effects of y-H2AX foci are still poorly understood, two theories have been proposed that may not be mutually exclusive [17,18], The first model suggests that the post-translational modification may impart structural transitions to DSB domains, and the second implicates the histone variant as a signaling intermediate in the repair pathway. 

From all the above it would be expected that only histone variability (variants or post-translational modification) affecting the histone fold or C-terminal domains would have a major effect on nucleosome stability in agreement with the experimental results that will be described in the following sections. 

Histone acetylation is without a doubt one of the most thoroughly characterized post-translational modifications of histones where both the functional (see Section 3.1) and structural implications for chromatin have been explored. In the sections that follow we are going to summarize the major structural effects of this post-translational modification as they pertain to the nucleosome and the chromatin fiber. 

AFM assessment of structural effects of histone post-translational modifications... 

Intact plants are also suitable for cost-effective production of recombinant pharmaceutical proteins providing products free of contaminations with endotoxins or human pathogens. Plants generally promote the proper fold of foreign proteins and post-translational modifications that are somehow similar to those of mammalian systems. Also, production of vaccine candidates in cereal seeds allows antigen protection from proteolysis which ensures their stability for a long period of time. 

D. J. Graves, B. L. Martin J. H. Wang (1994) Co- and Post-Translational Modification of Proteins Chemical Principles and Biological Effects, pp. 348ff, Oxford University Press, Oxford. 

Other post-translational modifications of proteins (e.g., phosphorylation) are extremely important mechanisms of regulation of enzyme activity. Very tittle work has been done on the effects of such modifications on enzyme stabilization. 

With respect to sample preparation, it is necessary to develop effective and fast procedures involving only a few steps in order to avoid contamination, reduce analysis time and to improve the quality of analytical work. Microsampling and the use of smaller sample sizes is required and also the further development of analytical techniques. In particular, there is a need for the development of online and/or hyphenated techniques in ICP-MS. Microsampling combined with the separation of small amounts of analytes will be relevant for several chromatographic techniques (such as the development of micro- and nano-HPLC). There is a demand for further development of the combination of LA-ICP-MS as an element analytical technique with a biomolecular mass spectrometric technique such as MALDI- or ESI-MS for molecular identification and quantification of protein phosphorylation as well as of metal concentrations, this also enables the study of post-translational modifications of proteins, e.g. phosphorylation. 

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