Patent ID: 7481994

Claim:
A method of detecting intracellular calcium store levels in a cell, the method comprising: detecting a calcium biosensor polypeptide (CBP) distribution pattern in a cell comprising the CBP, wherein the CBP comprises a detectable domain operably linked to a stromal interaction molecule (STIM) polypeptide, wherein the STIM polypeptide comprises, from N-terminus to C-terminus, an EF-hand domain, a sterile alpha motif (SAM) domain, a transmembrane domain, and an ezrin-radixin-moesin (ERM) domain, wherein said EF-hand domain, SAM domain, transmembrane domain, and ERM domain are each of mammalian origin, by detecting a pattern of a detectable signal of the detectable domain in the cell; wherein the CBP distribution pattern is indicative of intracellular calcium store levels in the cell.