D. Clapham
Jan 27, 1995
Citations
58
Influential Citations
1,395
Citations
Quality indicators
Journal
Cell
Abstract
Ionized calcium (Ca 2÷) is the most common signal transduction element in cells ranging from bacteria to specialized neurons. Unlike many other second-messenger mo!ecules, Ca 2÷ is required for life, yet prolonged high intracellular Ca 2÷ levels lead to cell death. Ca 2+ cannot be metabolized like other second-messenger molecules, so cells tightly regulate intracellular levels through numerous binding and specialized extrusion proteins. Normal intracellular Ca 2+ levels at 100 nM are 20,000-fold lower than the 2 mM concentration found extracellularly. Scores of cellular proteins have been adapted to bind Ca 2+ tightly, in some cases simply to buffer or lower free Ca 2+ levels, and in others to trigger second-messenger pathways. The well-known basic elements in Ca 2÷ signal transduction have been extensively reviewed (Berridge, 1993; Carafoli, 1992; Clapham and Neer, 1993; Pozzan et al., 1994; Rhee, 1991; Tsien and Tsien, 1990). The aim of this review is to highlight recent findings in Ca 2+ signaling and to discuss their implications.