Factor Signal Transduction Systems

R Genes Cis Elements, Trans-factors and Signal Transduction Systems in the Lens, Joram Piatigorksy and Peggy S. Zelen-ka, National Eye Institute, National Institutes of Health, Maryland. Subject Index. 

Specific vanadium-induced alterations in the activity or expression level of components of metabolic pathways are described here. Many of these changes are not caused by alterations in the pathway enzymes themselves but in enzymes and factors involved in regulation, commonly referred to as signal transduction systems. Section 11.3 will discuss the alterations described in this section in the context of general signal transduction processes affected by vanadium. 

Study of the kinases which can be activated by the IL-6 family suggested that their signal transduction system may differ from those of growth factors. It also suggested that some kind of tyrosine phosphorylation is involved in the process (Hoffman-Liebermann and Liebermann, 1991a Lord et al., 1991 Michishita et al., 1991 Murakami et al., 1991). 

Sogaard-Andersen, L. and Kaiser, D. (1996). G factor, a cell-surface-associated intercellular signaling protein, stimulates the cytoplasmic Frz signal transduction system in Myxococcus xanthus. Proc. Natl. Acad. Sci. U.S.A. 93, 2675-2679. 

Fractalkine was first documented as a factor induced by TNF-a, interleukin-1 (IL-1), and bacterial lipopolysaccharide (LPS) (Bazan et al, 1997). TNF-a, IL-1, and LPS stimulate a similar spectrum of signal-transduction systems and activate both nuclear factor-KB (NF-kB) and mitogen-activated protein kinases (MAPKs). In rat aortic endothelial cells, the induction of fractalkine by these agonists is mediated through the NF-kB system (Garcia et al., 2000). 

The regulation of the total peripheral resistance also involves the complex interactions of several mechanisms. These include baroreflexes and sympathetic nervous system activity response to neurohumoral substances and endothelial factors myogenic adjustments at the cellular level, some mediated by ion channels and events at the cellular membrane and intercellular events mediated by receptors and mechanisms for signal transduction. As examples of some of these mechanisms, there are two major neural reflex arcs (Fig. 1). Baroreflexes are derived from high-pressure barorecep-tors in the aortic arch and carotid sinus and low-pressure cardiopulmonary baroreceptors in ventricles and atria. These receptors respond to stretch (high pressure) or... 

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