Calcium: just a chemical switch?
The calcium-signature hypothesis has evolved as a concept to explain specificity in signaling pathways that utilise calcium as a second messenger. In plant biology, this hypothesis was purely conceptual and based only upon correlative observations until recently. In the past few years, however, empirical data have emerged from experiments that were specifically designed to tackle the question of how specificity is encoded by calcium. In light of the attractive calcium-signature hypothesis, other potential explanations for signalling specificity have been overshadowed and ignored: it has been assumed that the calcium-signature dogma will explain all plant calcium signaling. However, there is a good deal of evidence supporting a counter-hypothesis in which calcium does not itself encode specificity but is merely an essential 'switch' in signaling. At the very least, both hypotheses are likely to be true in different situations, and it may well be that the calcium-signature hypothesis describes the exception rather than the rule.
Scrase-Field
Sarah A M G
SA
Division of Cell Sciences, University of Southampton, Bassett Crescent East, Southampton SO17 1BJ, UK. ssf1@soton.ac.uk
Knight
Marc R
MR
D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D020013:Calcium Signaling / Q000235:genetics / Q000502:physiology; D002147:Calmodulin / Q000031:analogs & derivatives / Q000235:genetics / Q000378:metabolism; D019441:Plant Epidermis / Q000187:drug effects / Q000502:physiology*; D010944:Plants / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases
D002118:Calcium; D002147:Calmodulin; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases