Patent ID: 8410043

Claim:
An isolated protein comprising a stabilized activin IIB receptor polypeptide (svActRIIB) wherein said polypeptide is selected from the group consisting of: (a) a polypeptide consisting of the sequence set forth in SEQ ID NO: 2, except for a single amino acid substitution at position 28, and a single amino acid substitution at position 44, wherein the substitution at position 28 is selected from the group consisting of W and Y, and the substitution at position 44 is T; (b) a polypeptide consisting of the sequence set forth in amino acids 19 through 134 of SEQ ID NO: 2, except for a single amino acid substitution at position 28, and a single amino acid substitution at position 44, wherein the substitution at position 28 is selected from the group consisting of W and Y, and the substitution at position 44 is T; (c) a polypeptide consisting of the sequence set forth in amino acids 23 through 134 of SEQ ID NO: 2, except for a single amino acid substitution at position 28, and a single amino acid substitution at position 44, wherein the substitution at position 28 is selected from the group consisting of W and Y, and the substitution at position 44 is T; (d) a polypeptide consisting of the sequence set forth in amino acids 25 through 134 of SEQ ID NO: 2, except for a single amino acid substitution at position 28, and a single amino acid substitution at position 44, wherein the substitution at position 28 is selected from the group consisting of W and Y, and the substitution at position 44 is T; (e) a polypeptide of any one of (a) through (d), except for a single amino acid substitution at position 28, and a single amino acid substitution at position 44, wherein the substitution at position 28 is selected from the group consisting of W and Y, and the substitution at position 44 is T, wherein the polypeptide is capable of binding myostatin, activin A, or GDF-11.