Calcium pumps isoforms

Hilfiker, H., Strehler-Page, M.A., Stauffer, T.P., Carafoli, E., Strehler, E.E., 1993, Structure of the gene encoding the human plasma membrane calcium pump isoform 1. J Biol Chem 268, 19717-19725. 

Lee, W.J., Roberts-Thomson, S.J., Holman, N.A., May, F.J., Lehrbach, G.M., Monteith, G.R., 2002, Expression of plasma membrane calcium pump isoform mRNAs in breast cancer cell lines. Cell Signal 14, 1015-1022. 

Papp, B Enyedi, A., Paszty, K., Kov4cs, T., Sarkadi, B., G dos, G., Magnier, C Wuytack, F., Enouf, J. (1992). Simultaneous presence of two distinct endoplasmic-reticulum-type calcium-pump isoforms in human cells. Biochem. J. 288,297-302. 

Genetic evidence supports the importance of coordinated expression and distributions of a2 or a3 Na+/K+ pump isoforms with the Na+/Ca2+ exchanger (NCX) and Ca2+ pumps to function in excitable and contractile cells deletion of one copy of the a2 Na+/K+ pump gene in mice leads to increased contractile force in cardiac and skeletal muscle while deletion of one copy of the al gene leads to reduction of contractile force [25]. In rat optic nerve astrocytes, deletion of the a2 gene or ouabain treatment of cells expressing a2 leads to increased capacitative calcium entrance responses, which reflect a decreased ability to rapidly remove cytosolic Ca2+ [26]. 

The smooth endoplasmic reticulum calcium pumps (SERCA) found in brain were first identified in sarcoplasmic reticulum. The three isoforms of SERCA are products of separate genes SERCA-1 is expressed in fast-twitch skeletal muscle SERCA-2a in cardiac/slow-twitch muscle SERCA-2b, an alternatively spliced form, is expressed in smooth muscle and non-muscle tissues SERCA-3 is... 

Periasamy, M., and Kalyanasundaram, A., 2007, SERCA pump isoforms Their role in calcium transport and disease. Muscle Nerve. 

Strehler, E.E., Zacharias, D.A., 2001, Role of alternative splicing in generating isoform diversity among plasma membrane calcium pumps. Physiol Rev 81, 21—50. 

Lytton, J., Westlin, M Burk, S.E., Shull, G E., MacLennan, D.H. (1992). Functional comparisons between isoforms of the sarcoplasmic or endoplasmic reticulum family of calcium pumps. J. Biol. Chem. 267,14483-14489. 

Calcium pumps, also termed Ca +-ATPase, are calcium channels that transport calcium from the low concentration cytoplasm to the high concentration extracellular space or ER/SR lumenal side using the energy of ATP hydrolysis. Based on their locations, calcium pumps are classified into two groups, plasma membrane Ca +-ATPase (PMCA) and sarcoplasmic reticulum Ca +-ATPase (SERCA). " Four basic isoforms of PMCA (PMCAl 4) have been identified and the other PMCA isoforms are the alternative splicing products of the basic isoforms. PMCAl and 4 are ubiquitously expressed in different tissues and PMCA2 and 3 are expressed in nerve cells. Three basic isoforms of SERCA pump and several sphcing variants have also been identified. ... 

SERCA pumps in cultured COS cells. Their functional properties were studied using isolated microsomes. The initial in vitro studies reported that SERCA1 and SERCA2a isoforms shared similar Ca2+ affinity and velocity of Ca2+ uptake (Vmax). Subsequently, a higher kinetic turnover was demonstrated for the SERCA1 compared with the SERCA2a isoform (5.0- versus 2.6-fold increase in calcium uptake rate) (Sumbilla et al 1999). 

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