As a result of several researches, which were carried out during the last few decades, it has been established that a variety of different ion channels exist in all plant cells of all the species (Sanders, et. al1999). Additionally, mechanically gated ion channels in plant cells prevent lysis that arises during hypo-osmotic stress and also set cell of the free osmolytes (Hwang, et. el2000). Detached calcium- anion- and potassium channels in the vacuolar and plasma membranes of plant cells (Essah P.A., et al. 2003) have been categorized and identified by patch clamping (Roberts, et. al1997).
The electro-physical analysis, which was carried out on Escherichia coli’s inner membrane, had made it possible to identify the existence of three discrete mechanic-sensitive activities. Although, recent discoveries of the genes made the evidence of two of mentioned activities: small conductance and large mechanic-sensitive channels. (Ward, et. el 2009) Genetic and electrophysiological analysis of these family members has provided insight into how do organisms use mechanic-sensitive channels for osmotic regulation as a reaction on changing of the environmental and developmental circumstances. Ion channels of some plants, such as, SLAC and ALMT anion channel subunits, are distinctive (Hille, 2001). Many families of the plant with ion channel depict their homology to the animal genes. Examples of such families are: cyclic nucleotide-gated channels, ion-tropic glutamate receptor homologs, and both depolarization- and hyperpolarization-triggered Shaker-type potassium channels. These plant ion channels bring distinctive opportunities for evaluation of the structural mechanisms and functions of ion channels (Margaret, et. al2013).
Before a cell can possess the ability to generate specific Ca2+oscillations it must possess with tight regulation of the efflux, via Ca-ATPases, and influx it via Ca2+ channels (Jon, et. al2002). Binding of calmodulin to a N-terminal or C-terminal auto inhibitors regulates the Ca-ATPases of many animal and plant cells (Dreyer, et. al2004).
Though some plants with Ca-ATPases have truncations at the N-terminus, that cause an ability to subdue yeast mutants that are defective in endomembrane Ca2+ transport, just like CAX1. However, the N-terminal auto-inhibitory mechanisms of plant with Ca-ATPases and CAX1 differ (Demidchik, et. al2002).
Ca-channels and Ca-ATPase in sarco (endo) plasmic reticulum are widespread and play an important role in the metabolism of calcium in various tissues (Hille, 2001). In different types of muscles, the functional activity of which is regulated by cyclic changes of the level of Ca2+ in the cytoplasm. These membrane systems play a key role in the regulation of contraction and relaxation.
In some plant with Ca-ATPases, the auto-inhibitory domain binds to hydrophilic loops and stalk region closer to the N-terminus. No matter the specifics of inhibition, the activation of the Ca-ATPases in animals and plants involves the detecting of Ca2+ fluxes, which activates the calmodulin (Jon, et. al2002).
References
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Membrane transport in plants. Blackwell, Oxford, pp 150–192
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Gene Families, Physiology, and Functional Genomics Analyses.Annual Review of Physiology.71:59-82.
- Margaret E. Wilson ,GrigoryMaksaev , and Elizabeth S. (2013).
MscS-like Mechanosensitive Channels in Plants and Microbes. Biochemistry, 52 (34), pp 5708–5722. Publication Date (Web): August 5, 2013.
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Mechanism of N-terminal Autoinhibition in theArabidopsis Ca2+/H+ Antiporter CAX1.The American Society for Biochemistry and Molecular Biology, Inc. Publication Date (Web): March 15, 2002.
