Glycogen synthase kinase-3 inhibitors

Abstract

Novel peptide inhibitors of GSK-3, compositions containing same and uses thereof are disclosed. The novel peptide inhibitors are substrate-competitive inhibitors and have an amino acid sequence designed so as to bind to a defined binding site subunit in GSK-3. Also disclosed are GSK-3 substrate competitive inhibitors which bind to the defined binding site subunit in the enzyme. Also disclosed are mutants of GSK-3 and uses thereof for identifying a putative GSK-3 substrate competitive inhibitor.

What is claimed is: 
     
         1 . A peptide having the amino acid sequence I:
   [Y n  . . . Y 1 ]ZX 1 X 2 X 3 S( p )[W 1  . . . W m]   (I)
   wherein,   m equals 1 or 2;   n is 3, 4, 5, 6 or 7, such that said peptide consists of 10 to 13 amino acid residues;   S(p) is a phosphorylated serine residue or a phosphorylated threonine residue;   Z is any amino acid residue excepting serine residue or threonine residue;   X 1 , X 2 , Y 1 -Yn and W 1 -Wm are each independently any amino acid residue; and   X 3  is a hydrophobic amino acid residue.   
     
     
         2 . The peptide of  claim 1 , wherein X 3  is selected from the group consisting of a proline residue and an alanine residue. 
     
     
         3 . The peptide of  claim 1 , wherein X 3  is a proline residue. 
     
     
         4 . The peptide of  claim 1 , wherein each of X 1 , X 2  and X 3  is a hydrophobic amino acid residue. 
     
     
         5 . The peptide of  claim 4 , wherein each of X 1 , X 2  and X 3  is independently selected from the group consisting of a proline residue and an alanine residue. 
     
     
         6 . The peptide of  claim 5 , wherein X 1  and X 2  are each a proline residue. 
     
     
         7 . The peptide of  claim 1 , wherein S(p) is a phosphorylated serine. 
     
     
         8 . The peptide of  claim 1 , wherein Z is an alanine residue. 
     
     
         9 . The peptide of  claim 1 , wherein m is 1 and W 1  is a proline residue. 
     
     
         10 . The peptide of  claim 1 , wherein n is 5. 
     
     
         11 . The peptide of  claim 10 , wherein Y 1 -Y 5  has the amino acid sequence Lys-Glu-Ala-Pro-Pro. 
     
     
         12 . The peptide of  claim 1 , having an amino acid sequence selected from the group of amino acid sequences as set forth in SEQ ID NOS:11-13 and 16. 
     
     
         13 . The peptide of  claim 1 , consisting of the amino acid sequence as set forth in SEQ ID NO:16. 
     
     
         14 . The peptide of  claim 1 , further comprising a hydrophobic moiety attached thereto. 
     
     
         15 . The peptide of  claim 14 , wherein said hydrophobic moiety is selected from the group consisting of a fatty acid and a fatty acid attached to an amino acid residue. 
     
     
         16 . The peptide of  claim 15 , wherein said fatty acid is myristic acid. 
     
     
         17 . The peptide of  claim 16 , consisting of the amino acid sequence as set forth in SEQ ID NO:17. 
     
     
         18 . A pharmaceutical composition comprising, as an active ingredient, the peptide of  claim 1 , and a pharmaceutically acceptable carrier. 
     
     
         19 . The pharmaceutical composition of  claim 18 , being packaged in a packaging material and identified in print, on or in said packaging material, for use in inhibiting an activity of GSK-3. 
     
     
         20 . The pharmaceutical composition of  claim 18 , being packaged in a packaging material and identified in print, on or in said packaging material, for use in the treatment of a biological condition associated with GSK-3 activity. 
     
     
         21 . A pharmaceutical composition comprising, as an active ingredient, the peptide of  claim 14 , and a pharmaceutically acceptable carrier. 
     
     
         22 . A method of inhibiting an activity of GSK-3, the method comprising contacting cells expressing GSK-3 with an effective amount of the peptide of  claim 1 . 
     
     
         23 . A method of treating a biological condition associated with GSK-3 activity, the method comprising administering to a subject in need thereof a therapeutically effective amount of the peptide of  claim 1 . 
     
     
         24 . A method of inhibiting an activity of GSK-3, the method comprising contacting cells expressing GSK-3 with an effective amount of the peptide of  claim 14 . 
     
     
         25 . A method of treating a biological condition associated with GSK-3 activity, the method comprising administering to a subject in need thereof a therapeutically effective amount of the peptide of  claim 14 . 
     
     
         26 . A GSK-3 substrate competitive inhibitor capable of interacting with at least one amino acid within the catalytic binding site of a GSK-3 enzyme, said at least one amino acid comprising a phenylalanine residue at position 93, or an equivalent thereof of said GSK-3 enzyme. 
     
     
         27 . A method of identifying a putative substrate competitive inhibitor of GSK-3, the method comprising screening a plurality of substances for a substance capable of interacting with a phenylalanine residue at position 93, or an equivalent thereof, within a catalytic binding site of GSK-3. 
     
     
         28 . The method of  claim 27 , comprising screening said plurality of substances for a substance which exhibits inhibition of at least 20% of an activity of a wild-type GSK-3 enzyme and which exhibits inhibition of less than 20% of said activity of a mutated GSK-3 enzyme, said mutated GSK-3 enzyme comprising an amino acid substitution with respect to position Phe93, or an equivalent thereof, of a corresponding wild-type GSK3 enzyme. 
     
     
         29 . The method of  claim 28 , wherein said screening comprises:
 determining said activity of said wild-type GSK-3 enzyme in the presence and absence of each of said substances, thereby determining a level of inhibition of said activity of said wild-type GSK-3 enzyme exhibited by each of said substances;   determining said activity of said mutated GSK-3 enzyme in the presence and absence of each of said substances, thereby determining a level of inhibition of said activity of said mutated GSK-3 enzyme exhibited by each of said substances; and   comparing said levels of inhibition.   
     
     
         30 . The method of  claim 27 , wherein said screening comprises computationally screening said plurality of substances for a substance capable of interacting with a phenylalanine residue at position 93, or an equivalent amino acid thereof, within a set of atomic structural coordinates defining a three-dimensional atomic structure of a GSK-3 enzyme. 
     
     
         31 . An isolated polypeptide comprising an amino acid sequence of a mutated GSK-3 enzyme, wherein an amino acid sequence of said mutated GSK-3 enzyme comprises at least one amino acid substitution with respect to position Asp90, Lys91, Arg92, Phe93 and/or Lys94 of a corresponding wild-type GSK3 enzyme.