SERCA-Type of Calcium Pumps and Phospholamban

Re: Thanx

Leonard DODE

On Mon Dec 14, grover wrote
>Dr. Leonard:
>  Another way to look at it may be that SERCA3 control occurs mainly in an area where it is not advantageious to reach a very low Ca concentration.

>On Mon Dec 14, Leonard DODE wrote
>>On Sat Dec 12, grover wrote
>>>  Thanx for the response. I have considered the PMCA pumps more for cell survival and SERCA pumps more for signal transduction (Grover 1985, Cell Calcium). What do you think of that idea?

>>>Dear dr. Grover,
>>Indeed, the general idea is that SERCA pumps are required for the termination of the transient calcium signal after cell stimulation together with the concerted action of PMCA pumps and/or sodium-calcium exchanger. But, let's not forget that SERCA1, SERCA2, and PMCA display high affinities for calcium and in normal condition this might be sufficient for a cell to survive the transitory increases in cytosolic calcium concentration. What about SERCA3 with its low calcium affinity? It appears it would function at 'abnormal' high calcium concentration. That's why I suggested it might be a benefit for a cell to express SERCA3 in order to overcome accidental or/and induced cytosolic calcium increases.
Dear Dr. Grover,
Indeed, that is another angle to look at it! However, this view brings us back to the existence of different cytosolic regions characterized by opposite calcium concentrations, doesn't it?
Thanks again for your interest and questions,

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