Calcium Ion Leakage Inhibitors

摘要

A polypeptide exhibiting the effect of inhibiting Ca²⁺ leakage in a target cell, the polypeptide having the amino acid sequence of any of SEQ ID NOs: 3 to 9 or an amino acid sequence obtained through deletion, insertion, substitution, or addition of one or more amino acids in the aforementioned amino acid sequence; a polynucleotide encoding the polypeptide; and a pharmaceutical composition containing, as an active ingredient, the polypeptide or an expression product of the polynucleotide. The polypeptide of the present invention exhibits the effect of inhibiting Ca²⁺ leakage in the endoplasmic reticulum of a target cell, and therefore is useful as a therapeutic or preventive agent for, for example, diseases associated with abnormal intracellular calcium handling. The polypeptide can be employed for selecting, through screening, a compound exhibiting an activity of enhancing or suppressing the Ca²⁺ leakage inhibitory effect in the endoplasmic reticulum of a target cell.