Provided is a composition comprising
a peptide comprising amino acids and / or
amino acid analogs comprising a continuous sequence of a
sclerostin fragment comprising Tyr43 or Tyr213. Also provided is a composition comprising
a peptide comprising less than about 75 amino acids and / or
amino acid analogs including an
amino acid or amino acid analog capable of being sulfated, where the composition is capable of inhibiting
sclerostin binding to an LRP. Further provided is a composition comprising
a peptide comprising less than about 75 amino acids and / or amino acid analogs including an amino acid or amino acid analog capable of being post-translationally sulfated, where the composition is capable of inhibiting binding of a
protein ligand comprising a
sulfation site to its binding partner. Additionally provided is a method of enhancing a
Wnt signaling pathway comprising contacting an LRP5 / 6
receptor in the
Wnt signaling pathway with either of the above-described compositions that comprise a sequence of a
sclerostin fragment or is capable of inhibiting sclerostin binding to an LRP, where the
tyrosine or
tyrosine analog is not sulfated, in a manner sufficient to enhance the
Wnt signaling pathway. Further provided is a method of treating a subject having a
disease exacerbated by inhibition of a Wnt signaling pathway comprising administering either of the above-described compositions that comprise a sequence of a sclerostin fragment or is capable of inhibiting sclerostin binding to an LRP, where the
tyrosine or tyrosine analog is not sulfated, to the subject in a manner sufficient to reduce the inhibition of the Wnt signaling pathway. Also, a method of inhibiting binding of a
protein ligand comprising a
sulfation site to its binding partner is provided. The method comprises adding the above-described composition that is capable of inhibiting binding of a
protein ligand to its binding partner to the
protein ligand and its binding partner in a manner sufficient to inhibit binding of the
protein ligand to its binding partner.