DRG11-responsive (DRAGON) gene and uses thereof

Abstract

This invention features methods and compositions useful for treating and diseases caused by a dysregulation of the BMP/GDF branch of the TGF-β signaling pathway. Also disclosed are methods for identifying compounds useful for such therapy.

1 . A method for identifying a compound that modulates a TGF-β signaling pathway, said method comprising the steps of: 
 a. providing a sample comprising a DRAGON protein and a TGF-β signaling pathway member;    b. contacting said sample with a candidate compound; and    c. assessing the binding of said DRAGON protein to said TGF-β signaling pathway member in said sample in the presence of said candidate compound relative to binding in the absence of said candidate compound, wherein a compound that modulates binding of said DRAGON protein to said TGF-β signaling pathway member is identified as a compound that modulates a TGF-β signaling pathway.    
     
     
         2 . The method of  claim 1 , wherein said TGF-β signaling pathway is the BMP/GDF pathway.  
     
     
         3 . The method of  claim 1 , wherein said TGF-β signaling pathway member is a bone morphogenetic protein (BMP).  
     
     
         4 . The method of  claim 3 , wherein said BMP is BMP-2 or BMP-4.  
     
     
         5 . The method of  claim 3 , wherein said BMP is labeled with a radioisotope.  
     
     
         6 . The method of  claim 5 , wherein said BMP is [ 125 I]-BMP-2 or [ 125 I]-BMP-4.  
     
     
         7 . The method of  claim 1 , wherein said TGF-β signaling pathway member is a type I BMP receptor.  
     
     
         8 . The method of  claim 7 , wherein said type I BMP receptor is ALK2, ALK3, or ALK6.  
     
     
         9 . The method of  claim 1 , wherein said TGF-β signaling pathway member is a type II BMP receptor.  
     
     
         10 . The method of  claim 9 , wherein said type II BMP receptor is BMPRII, ActRIIA, or Act RIIB.  
     
     
         11 . The method of  claim 1 , wherein the assessing step (c) comprises the use of a DRAGON-specific antibody.  
     
     
         12 . The method of  claim 1 , wherein the assessing step (c) comprises the use of an antibody specific for the TGF-β signaling pathway member.  
     
     
         13 . A method for identifying a compound that modulates a TGF-β signaling pathway, said method comprising the steps of: 
 a. providing a cell that expresses a type I BMP receptor, a type II BMP receptor, and an intracellular TGF-β signaling pathway member;    b. contacting said cell with DRAGON and a candidate compound; and    c. assessing the level of activation of the TGF-β signaling pathway by assessing the activation of said intracellular TGF-β signaling pathway member relative to the level of activation in the absence of said candidate compound, wherein a compound that modulates the activation of said intracellular TGF-β signaling pathway member is identified as a compound that modulates a TGF-β signaling pathway.    
     
     
         14 . The method of  claim 13 , wherein said TGF-β signaling pathway is the BMP/GDF pathway.  
     
     
         15 . The method of  claim 13 , wherein said type I BMP receptor is ALK2, ALK3, or ALK6.  
     
     
         16 . The method of  claim 13 , wherein said type II BMP receptor is BMPRII, ActRIIA, or ActRIIB.  
     
     
         17 . The method of  claim 13 , wherein said intracellular TGF-β signaling pathway member is an R-Smad.  
     
     
         18 . The method of  claim 17 , wherein said R-Smad is Smad1, Smad5, or Smad8.  
     
     
         19 . The method of  claim 13 , wherein the assessing step (c) comprises assessing the phosphorylation state of said intracellular TGF-β signaling pathway member.  
     
     
         20 . The method of  claim 13 , wherein the assessing step (c) comprises assessing the binding of said intracellular TGF-β signaling pathway member to a second intracellular protein.  
     
     
         21 . The method of  claim 20 , wherein said second intracellular protein is a Co-Smad.  
     
     
         22 . The method of  claim 13 , wherein said contacting step (b) further comprises contacting said cell with a TGF-β ligand.  
     
     
         23 . The method of  claim 22 , wherein said TGF-β ligand is BMP-2, BMP-4, BMP-7, or GDF-5.  
     
     
         24 . The method of  claim 13 , wherein said DRAGON is recombinantly expressed by said cell.  
     
     
         25 . A method for identifying a compound that modulates a TGF-β signaling pathway, said method comprising the steps of: 
 a. providing a cell that expresses a reporter gene construct operably linked to a TGF-β ligand-dependent promoter;    b. contacting said cell with DRAGON and a candidate compound; and    c. assessing the level of expression of said reporter gene relative to the level of expression of said reporter gene in the absence of said candidate compound, wherein a candidate compound that modulates the level of expression of said reporter gene is identified as a compound that modulates a TGF-β signaling pathway.    
     
     
         26 . The method of  claim 25 , wherein said TGF-β signaling pathway is the BMP/GDF pathway.  
     
     
         27 . The method of  claim 25 , wherein said reporter gene construct is the BRE-Luc construct.  
     
     
         28 . The method of  claim 25 , wherein the contacting step (b) further comprises contacting said cell with a TGF-β ligand.  
     
     
         29 . The method of  claim 25 , wherein said TGF-β ligand is BMP-2, BMP-4, BMP-7, or GDF-5.  
     
     
         30 . The method of  claim 25 , wherein said DRAGON is recombinantly expressed by said cell.  
     
     
         31 . The method of  claim 25 , wherein said cell further expresses a BMP type I receptor.  
     
     
         32 . The method of  claim 31 , wherein said BMP type I receptor is ALK2, ALK3, or ALK6.  
     
     
         33 . The method of  claim 25 , wherein said cell further expresses a BMP type II receptor.  
     
     
         34 . The method of  claim 33 , wherein said BMP type II receptor is BMPRII, ActRIIA, or ActRIIB.  
     
     
         35 . A method for identifying a compound that modulates cellular adhesion, said method comprising the steps of: 
 a. providing a sample comprising a DRAGON protein and an adhesion-modulating protein;    b. contacting said sample with a candidate compound; and    c. assessing the binding of said DRAGON protein to said adhesion-modulating protein in said sample in the presence of said candidate compound relative to binding in the absence of said candidate compound, wherein a compound that modulates binding of said DRAGON protein to said an adhesion-modulating protein is identified as a compound that modulates cellular adhesion.    
     
     
         36 . The method of  claim 35 , wherein said adhesion-modulating protein is a cadherin.  
     
     
         37 . The method of  claim 36 , wherein said cadherin is E-cadherin.  
     
     
         38 . The method of  claim 35 , wherein said adhesion-modulating protein is DRAGON.  
     
     
         39 . The method of  claim 35 , wherein said adhesion-modulating protein is DL-N.  
     
     
         40 . The method of  claim 36 , wherein said DRAGON protein and said cadherin are bound to microspheres.  
     
     
         41 . The method of  claim 36 , wherein said DRAGON protein and said cadherin are present on the plasma membrane of a cell.