Abstract: A method for detecting influx of calcium ions into a eukaryotic cell comprising providing a eukaryotic cell having a detectable reporter capable of translocation from the cytosol to associate with the plasma membrane in response to an influx of calcium ions, and, monitoring association of the detectable report with the plasma membrane and/or a decrease in the detectable report in the cytosol. The detectable report is preferably CAPRI or a derivative thereof and is preferably labelled with a fluorescent marker.

Abstract: A method for identifying a compound capable of promoting deactivation of, or inhibiting activation of, a membrane bound active small GTPase, comprising incubating a live cell expressing the small GTPase and having a small GTPase specific reporter thereof in the presence of a test compound and monitoring association of the reporter with the membrane bound small GTPase, wherein a change in association of the reporter with the membrane bound small GTPase is indicative that the test compound is capable of promoting deactivation of, or inhibiting activation of, the membrane bound small GTPase.