Phosphatidylinositols membrane potentials

The rate of formation of the complex at the interface is described by the rate constant Kr. It is important to note that Kr depends on the surface charge of the membrane. This is simply a consequence of the definition of KrI the number of associations per square centimeter per second is set equal to CmKr, where Cm is the bulk concentration of the cation in the aqueous phase. Now, as a consequence of the negative charge of, for example, the phosphatidylinositol membrane, the cation concentration Cm at the membrane surface is larger than the bulk concentration by a Boltzmann factor exponent ( —4>), where cj) is the electric potential (expressed in units RT/F) at the membrane surface [330]. 

Glutamate-mediated Ca2+ entry through NMDA at the plasma membrane level and mobilization of Ca2+from intracellular stores through PLC-mediated generation of PtdIns-3/J is indispensable for the basal NF-kB activity. Three cytosolic Ca2+ sensors, calmodulin, protein kinases C (PKC), and the p2 l(ras)/phosphatidylinositol 3-kinase (Ptdlns-3K)/Akt pathways, are simultaneously involved in the steps linking the Ca2+ to NF-kB activity (Lilienbaum and Israel, 2003 Marchetti et al., 2004 Lubin et al., 2005). Calmodulin modulates calcineurin, a Ca2+-dependent protein phosphatase, which plays a role in the basal NF-kB activity, whilst stimulation of both the calmodulin kinase II and Akt kinase pathways results in the up-regulation of the transcriptional potential of the p65 subunit of NF-/cB (Lilienbaum and Israel,... 

Cullen, P. J., and Venkateswarlu, K. (1999). Potential regulation of ADP-ribosylation factor 6 signalling by phosphatidylinositol 3,4,5-trisphosphate. Biochem. Soc. Trans. 27, 683-689. Donaldson, J. G. (2003). Multiple roles for Arf6 Sorting, structuring, and signaling at the plasma membrane. J. Biol. Chem. 278, 41573-41576. Epub 2003 Aug 11. 

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