Glowing with Calcium

Science's STKE  23 May 2000:
Vol. 2000, Issue 33, pp. tw3
DOI: 10.1126/stke.2000.33.tw3

Proteins that luminesce when they bind calcium are useful tools for studying calcium signaling and homeostasis. Torrecilla et al. generated aequorin-expressing cyanobacteria to determine whether these bacteria used calcium as a signal in response to temperature shock. First, the authors characterized the calcium homeostasis mechanism and found a biphasic response to increases in extracellular calcium with the slower decay phase dependent on both the reduction of [Ca2+]i by calcium binding proteins and calcium transporters. Calcium transients were generated in response to both heat and cold shock. The mechanisms of increased [Ca2+]i were different: Increased [Ca2+]i produced by heat shock arises from calcium released from both intracellular stores and by influx from the extracellular space, and increased [Ca2+]i produced by cold shock arises from predominantly extracellular sources.

Torrecilla, I., Leganés, F., Bonilla, I., and Fernández-Piñas, F. (2000) Use of recombinant aequorin to study calcium homeostasis and monitor calcium transients in response to heat and cold shock in cyanobacteria. Plant Physiol. 123: 161-175. [Abstract] [Full Text]