The Role of a Ca2+ Switch in the Circadian Clock

We have identified two Ca2+ sensor proteins that act as a switch to turn on the evening genes in the circadian clock. This is the first switch identified in the circadian clock and provides new insights in to how plants measure time. We have shown that the Ca2+ sensor proteins CALMODULIN-LIKE 23 and 24 (CML23 and CML24) are part of the switch which is activated in the evening to regulate the “evening oscillator” of the circadian clock. We have also identified the genes in the circadian clock that are regulated by the Ca2+ switch. We predict that the Ca2+ switch function is to optimise the circadian clock during light to dark transitions, such as those that occur at dusk.

You will investigate the function of the Ca2+ switch by artificially inducing Ca2+ switching using pharmacological and genetic approaches. After artificial induction of the switch you will measure the consequence for circadian gene expression and the functioning of the circadian clock. You will also studying temporal and spatial regulation of CML23 and 24 proteins using confocal microscopy.