Cellular regulation process

The adsorption-desorption hysteresis does not disappear or decrease during at least a week of exposure of the NA sample to a r.h. of 56%, this value being chosen because the adsorption hysteresis is the greatest at this r.h. The hysteresis lifetime is great enough to consider the hysteresis as a permanent phenomenon for the processes of the cellular regulation. 

SUMOylation. Figure 1 SUMOylation is a reversible and regulated process. Target protein modification by SUMO can be initiated and terminated by different cues. Sumoylation leads to changes in the behavior of the modified protein, for example, different cellular localization, enhanced/reduced activity, or increased stability. These changes are due to alterations either in protein interactions or protein folding. 

Finally, natural (i )-(-)-mevalonolactone, a key intermediate from a broad spectrum of cellular biological processes and their regulation, was synthesised via eight steps in 55% overall yield and > 99% ee (Scheme 19). In the key step, the aforementioned enantioconvergent chemoenzymatic deracemization route was applied. Thus, 2-methyl-2-benzyl-oxirane ( )-2 g was deracemized on a large scale (10 g) using lyophilized cells of Nocardia EHl and sulfuric... 

Calcium is involved in the regulation of a multitude of cellular physiological processes, and also functions as an intracellular second messenger. Intracellular calcium concentrations can be increased by ... 

Cockayne, S.E., Rassl, D.M., and Thomas, S.E., 2000, Squamous cell carcinoma arising in Hailey-Hailey disease of the vulva. Br. J. Dermatol. 142, 540-542 Creemers, J.W., Jackson, R.S., and Hutton, J.C., 1998, Molecular and cellular regulation of prohormone processing. Semin. Cell. Dev. Biol. 9, 3—10... 

Adenovirus vectors are known to be taken into cells by endocytosis and to be released from endosomes by a well regulated process, assumed to be highly efficient [84]. It is therefore somewhat surprising that PCI is able to increase the number of adenoviral transduced cells by up to 30-fold. Nevertheless, PCI with adenoviral vectors has been tested in several different cell lines, and in all cases improved transduction has been observed [85]. The adenovirus activated by means of PCI seems to follow the same cellular pathways as for conventional adenovims infection, i.e., the fraction of transduced cells followed a linear relationship with the Coxsackie and Adenoviral Receptor (CAR) level of the cells and is integrin dependent. Furthermore, PCI increase the number of nuclearly located viral DNA molecules as measured by real-time PCR and fluorescence in situ hybridization (FISH) [86]. The results so far indicate that the main cause of the PCI effect on transduction with adenovirus is related to enhanced release of the viral particles from the endocytic vesicles into the cytosol. In accordance with what has been found for PCI of plasmids the adenovirus may be delivered after the photochemical treatment (unpublished results). However, adenovirus may be delivered up to 12 h after the photochemical treatment, which is longer than what is effective for PCI of plasmids [43, 87]. 

Activation of caspases is irreversible, because it involves peptide-bond cleav e. This is unlike most other protein modifications which play a role in cellular regulation. Therefore, proteolysis is involved only in unidirectional, irreversible processes, such as the cell cycle and cell death. But, the possibilities to regulate irreversible reactions are rather limited. In a cascade of proteolytic reactions, the first enzyme in the chain is the most likely point of control. This is the initiator caspase. The signals controlling initiator caspases vary, there are both external and internal signals (Fig. 13.5). Several mechanisms control the irreversible activation of caspases, including phosphorylation, separation, and compartmentalization of pro-caspases and positive and n ative regulators. 

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