Patent ID: 7713713
Filing Date: 2010-05-11
Classification: C07K,C12N,G01N

Abstract:
1. A polypeptide having an intracellular calcium ion indicator function, which comprises the following elements (a)-(c): (a) a polypeptide residue consisting of a membrane localization signal sequence; (b) a first fluorescent polypeptide residue; and (c) a second fluorescent polypeptide residue in the order of (a), (b) and (c) from the N-terminal side, wherein one of said two fluorescent polypeptide residues is a donor for fluorescence resonance energy transfer, the other is the corresponding acceptor, and said two fluorescent polypeptide residues are connected with a linker polypeptide residue comprising at least one calpain sensitive sequence, thereby to allow fluorescence resonance energy transfer between them, and wherein the polypeptide having an intracellular calcium ion indicator function is not cleaved by calpain at the calpain sensitive sequence in the linker polypeptide residue when expressed in a cell.