Physics – Biological Physics
Scientific paper
2003-06-14
Michael Graupner, Frido Erler, Michael Meyer-Hermann, A Theory of Plasma Membrane Calcium Pump Stimulation and Activity, Journ
Physics
Biological Physics
24 pages, 6 figures
Scientific paper
10.1007/s10867-005-4472-2
The ATP-driven Plasma Membrane Calcium pump or Ca(2+)-ATPase (PMCA) is characterized by a high affinity to calcium and a low transport rate compared to other transmembrane calcium transport proteins. It plays a crucial role for calcium extrusion from cells. Calmodulin is an intracellular calcium buffering protein which is capable in its Ca(2+) liganded form of stimulating the PMCA by increasing both the affinity to calcium and the maximum calcium transport rate. We introduce a new model of this stimulation process and derive analytical expressions for experimental observables in order to determine the model parameters on the basis of specific experiments. We furthermore develop a model for the pumping activity. The pumping description resolves the seeming contradiction of the Ca(2+):ATP stoichiometry of 1:1 during a translocation step and the observation that the pump binds two calcium ions at the intracellular site. The combination of the calcium pumping and the stimulation model correctly describes PMCA function. We find that the processes of calmodulin-calcium complex attachment to the pump and of stimulation have to be separated. Other PMCA properties are discussed in the framework of the model. The presented model can serve as a tool for calcium dynamics simulations and provides the possibility to characterize different pump isoforms by different type-specific parameter sets.
Erler Frido
Graupner Michael
Meyer-Hermann Michael
No associations
LandOfFree
A theory of Plasma Membrane Calcium Pump stimulation and activity does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A theory of Plasma Membrane Calcium Pump stimulation and activity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A theory of Plasma Membrane Calcium Pump stimulation and activity will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-488982