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Calcium Transport

Molecular and Cellular Aspects of Calcium Transport

Dr. Giuseppe Inesi

Our laboratory has been engaged in a long-term research project, Molecular and Cellular Aspects of the Ca2+ Transport ATPase. This enzyme is a membrane-bound protein that utilizes ATP for active transport of Ca2+, and is required for the intracellular storage of Ca2+. In turn, release of the stored Ca2+ is required for intracellular signaling and initiation of most cellular functions as a second messenger.

Our molecular studies include determination of enzyme and transport kinetics, protein chemistry and derivatization of various amino acid residues, and production of recombinant protein to obtain specific mutations and assess their effects on catalytic and transport function.

Cellular studies involve overexpression or silencing of the ATPase gene in cultured cells, and determination of functional consequences with regard to Ca2+ signaling and regulation of Ca2+-dependent functions.

This research is currently supported by a five-year National Institutes of Health (NIHLBI) award to Dr. Inesi.

References

  • Inesi G., Sumbilla, C., and Kirtley, M.E. Relationships of molecular structure and function in the Ca 2+ transport. ATPase. Physiology Review 7(3):749-760 (1990).
  • Toyoshima, C. and Inesi G., Structural Basis of Ion Pumping by Ca2+ ATPase of Sarcoplasmic Reticulum. In: Annual Review of Biochemistry 73:269-292 (2004).
  • Ma H, Sumbilla CM, Farrance IK, Klein MG, Inesi G. Cell-specific expression of SERCA, the exogenous Ca2+ transport ATPase, in cardiac myocytes. American Journal of Physiology and Cell Physiology 2004;286(3):C556-64 (2004).
  • Inesi G, Ma H, Lewis D, Xu C.: Ca 2+ occlusion and gating function of Glu309 in the ADP-fluoroaluminate analog of the Ca 2+-ATPase phosphoenzyme intermediate. Journal of Biological Chemistry 279:31629-37 (2004).
  • Hua S, Xu C, Ma H, Inesi G: Interference with phosphoenzyme isomerization and inhibition of the Ca2+ ATPase (SERCA) by 1,3-dibromo-2,4,6-tri(methylisothiouronium) benzene. Journal of Biological Chemistry 280: 17579-17583 (2005).
  • Ma H, Lewis D, Xu C, Inesi G, Toyoshima C. Functional and structural roles of critical amino acids within the 'N', 'P' and 'A' domains of the Ca2+ ATPase headpiece. Biochemistry 44:8090-8100 (2005).
  • Obara K., Miyiashita N., Xu C., Toyoshima I, Sugita Y. Inesi G., Toyoshima C.: Structural role of countertransport revealed in Ca2+ pump crystals structure in the absence of Ca2+. Proceedings of the National Academy of Science 102: 14489-14496 (2005).
  • Inesi G, Lewis D., Ma H., Prasad A. and Toyoshima C. Concerted conformational effects of Ca 2+ and ATP are required for activation of sequential reactions in the Ca 2+ ATPase (SERCA) catalytic cycle. Biochemistry, November issue, (2006).

Contact:
Dr. Giuseppe Inesi, ginesi@pacific.edu, 415.929.6674