Article ID Journal Published Year Pages File Type
1948929 Biochimica et Biophysica Acta (BBA) - General Subjects 2006 7 Pages PDF
Abstract

LIBRA is a fluorescent biosensor of inositol 1,4,5-trisphosphate (IP3) and is composed of the ligand-binding domain of the rat type 3 IP3 receptor and cyan and yellow fluorescent proteins. We examined the responses of LIBRA and its IP3-insensitive mutant LIBRA-N to compounds known to inhibit IP3-induced Ca2+ release. Heparin, a competitive antagonist of IP3 receptors, increased the emission ratio of LIBRA but not that of LIBRA-N. In contrast, 2-aminoethoxydiphenyl borate, a known non-competitive inhibitor of IP3 receptor, decreased the emission ratios of both LIBRA and LIBRA-N. Thus, the concurrent use of LIBRA-N with LIBRA identifies nonspecific responses. These results indicate that LIBRA and its mutant control can be used to detect specific agonists and antagonists of IP3 receptors. We also demonstrate the utility of LIBRA and LIBRA-N in discriminating between specific and nonspecific responses in intact cells.

Related Topics
Life Sciences Biochemistry, Genetics and Molecular Biology Biochemistry
Authors
, , , , ,