Patent ID: 8524683

Claim:
A method of decreasing cardiac contractility in a subject, the method comprising: introducing, into heart cells of the subject, an effective amount of an isolated nucleic acid molecule that encodes a variant phosphatase inhibitor-1 protein, wherein the nucleic acid molecule encodes a polypeptide having at least 90% identity to: (a) SEQ ID NO:6 or a fragment of SEQ ID NO: 6; (b) SEQ ID NO: 21 or a fragment of SEQ ID NO: 21; or (c) SEQ ID NO:16 or a fragment of SEQ 1D NO: 16, and wherein the polypeptide or the fragment comprises: (i) a constitutively phosphorylated amino acid at position 35, said constitutively phosphorylated amino acid being aspartic acid or glutamic acid, and (ii) a constitutively unphosphorylated amino acid at positions 67 and/or 75, wherein, the polypeptide or fragment inhibits the activity of rabbit protein phosphatase I and wherein expression of the encoded polypeptide decreases cardiac contractility in the subject.