Endoplasmic reticulum calcium pump expression and control of cell growth

Richard T. Waldron, Alison D. Short, Jennifer J. Meadows, Tarun K. Ghosh, Donald Gill

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Abstract

Intracellular Ca2+ pump expression and Ca2+ pool function are shown to be closely associated with growth and proliferation of DDT1MF-2 hamster smooth muscle cells. The Ca2+ pump blocker thapsigargin induces sustained Ca2+ pool emptying and entry of cells into a quiescent G0-like state (Short, A. D., Bian, J., Ghosh, T. K., Waldron, R. T., Rybak, S. L., and Gill, D. L. (1993) Proc. Natl. Acad. Sci. U. S. A. 90, 4986-4990). Using DDT1MF-2 cells growth-arrested by exposure to 3 μM thapsigargin for 24 h, treatment with 20% serum for 6 h without thapsigargin induced expression of functional Ca2+ pump protein detected as a 110-kDa thapsigargin-sensitive phosphorylated intermediate; 2.5% serum treatment resulted in no functional pump expression. Western analysis revealed only a slight serum-induced increase in total Ca2+ pump protein. New functional Ca2+ pump protein could be detected within 1 h of high serum treatment of thapsigargin- arrested cells, increasing over a 6-h period and correlating with the appearance of new Ca2+ pools. Induction of Ca2+ pools required serum at 10% or higher; no pools appeared with 5% serum or less. Significantly, high serum was required for only a brief but precise period of time. Exposure of thapsigargin-arrested cells to a 45-min pulse of 20% serum followed by continued culture in 2.5% serum was sufficient for full induction of new functional Ca2+ pump protein and Ca2+ pools; in contrast, no pumps or pools were detected after a 30-min serum pulse. A 40-min high serum pulse resulted in arrested cells reentering the cell cycle, synthesizing DNA, and resuming normal proliferation; in contrast, 35 min of serum treatment resulted in cells remaining totally quiescent. The results provide important evidence for the necessity of functional endoplasmic reticulum Ca2+ pumps in serum-induced cell growth and reflect a remarkably precise signaling period during which quiescent cells become committed to a progression of events including Ca2+ pump expression, Ca2+ pool function, reentry into the cell cycle, and cell division.

Original languageEnglish (US)
Pages (from-to)11927-11933
Number of pages7
JournalJournal of Biological Chemistry
Volume269
Issue number16
Publication statusPublished - Apr 22 1994

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All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

Waldron, R. T., Short, A. D., Meadows, J. J., Ghosh, T. K., & Gill, D. (1994). Endoplasmic reticulum calcium pump expression and control of cell growth. Journal of Biological Chemistry, 269(16), 11927-11933.