Ligands for EPH-like receptors

Abstract

Polypeptides which bind to one or more EPH-like receptors, particularly the HEK4 receptor, are described. The polypeptides are designated HEK4 binding proteins. Nucleic acids encoding HEK4 binding proteins, and expression vectors, host cells and processes for the production of the polypeptides are also described. The polypeptides are useful for modulating the growth and/or differentiation of a variety of tissues, including those from liver, kidney, lung, skin, digestive tract and nervous system and may be used to regenerate damaged or depleted tissue and to treat cancer or nervous system disorders.

1 . A purified and isolated polypeptide capable of binding at least one EPH-like receptor wherein the receptor is the HEK4 receptor.  
     
     
         2 . The polypeptide of  claim 1  wherein the binding results in activation of the EPH-like receptor.  
     
     
         3 . The polypeptide of  claim 1  which is human.  
     
     
         4 . The polypeptide of  claim 1  which is substantially free of other human proteins.  
     
     
         5 . The polypeptide of  claim 1  having in glyocosylated form an apparent molecular weight of about 21-27 kD on nonreducing SDS-PAGE.  
     
     
         6 . The polypeptide of  claim 1  which is characterized by being a product of procaryotic or eucaryotic expression of an exogenous DNA sequence.  
     
     
         7 . The polypeptide of  claim 6  wherein the exogenous DNA is cDNA, genomic DNA or synthetic DNA.  
     
     
         8 . The polypeptide of  claim 1  which has at least about 70% homology to the amino acid sequence as shown in  FIG. 3  (SEQ ID NO: 1).  
     
     
         9 . The polypeptide of  claim 1  which has the amino acid sequence of  FIG. 3  (SEQ ID NO: 1).  
     
     
         10 . The polypeptide of  claim 9  further comprising a methionine residue at position −1.  
     
     
         11 . The polypeptide of  claim 1  which is soluble or bound to a cell surface.  
     
     
         12 . The polypeptide of  claim 1  which is further capable of binding the ECK receptor.  
     
     
         13 . The polypeptide of  claim 1  which is multimeric.  
     
     
         14 . The polypeptide of  claim 13  selected from the group consisting of: an immunogloblin chimera, an antibody clustered protein, and covalently and noncovalently attached protein monomers.  
     
     
         15 . An isolated nucleic acid encoding a polypeptide capable of binding to at least one EPH-like receptor wherein the nucleic acid is selected from the group consisting of: 
 a) the nucleic acid as shown in  FIG. 3  (SEQ ID NO: 1);    b) nucleic acids which hybridize under conditions of 6×SSC and 65° C. with the coding region of  FIG. 3  (SEQ ID NO: 1); and    c) nucleic acids which are degenerate to the nucleic acids of (a) and (b).    
     
     
         16 . The nucleic acid of  claim 15  which is cDNA, genomic DNA or synthetic DNA.  
     
     
         17 . A polypeptide encoded by the nucleic acids of  claim 15 .  
     
     
         18 . The nucleic acids of  claim 15  which include one or more codons preferred for expression in  Escherichia coli.    
     
     
         19 . A biologically functional plasmid or viral vector including the nucleic acid of  claim 15 .  
     
     
         20 . A procaryotic or eucaryotic host cell stably transformed or transfected with a DNA vector of  claim 19 .  
     
     
         21 . The host cell of  claim 20  which is a CHO cell.  
     
     
         22 . The host cell of  claim 20  which is  Escherichia coli.    
     
     
         23 . A process for the production of a polypeptide capable of binding at least one EPH-like receptor comprising growing under suitable nutrient conditions procaryotic or eucaryotic host cells transformed or transfected with the nucleic acid of  claim 15  and isolating polypeptide products of the expression of the nucleic acids in the vector.  
     
     
         24 . A pharmaceutical composition comprising a therapeutically effective amount of the polypeptide of  claim 1  and a pharmaceutically acceptable adjuvant.  
     
     
         25 . The composition of  claim 24  wherein the polypeptide is of human origin.  
     
     
         26 . An antibody or fragment thereof specifically binding the polypeptide of  claim 1 .  
     
     
         27 . The antibody of  claim 26  which is a monoclonal antibody.  
     
     
         28 . A method of activating at least one EPH-like receptor comprising contacting the receptor with the polypeptide of  claim 1 .  
     
     
         29 . A method of modulating the growth or differentiation of cells comprising contacting the cells with the polypeptide of  claim 1 .  
     
     
         30 . The method of  claim 29  wherein the cells are kidney, lung, liver, skin, digestive tract, glial, nerve, or hematopoietic cells.  
     
     
         31 . A method of maintaining or restoring cellular function in the nervous system of a mammal comprising administering a therapeutically effective amount of the polypeptide of  claim 1 .  
     
     
         32 . A method of regenerating damaged or depleted tissue in a mammal comprising administering a therapeutically effective amount of the polypeptide of  claim 1 .  
     
     
         33 . The method of  claim 32  wherein the tissue is from liver, lung, digestive tract or nervous system.  
     
     
         34 . A method for detecting the presence of a polypeptide capable of binding at least one EPH-like receptor in a biological sample comprising: contacting the sample with the antibody of  claim 26  under conditions allowing for antibody binding to the polypeptide; and detecting the binding of the antibody.  
     
     
         35 . A method for detecting in a biological sample the presence of a nucleic acid encoding a polypeptide capable of binding at least one EPH-like receptor comprising: contacting the sample with the nucleic acid of  claim 15  under conditions allowing for hybridization; and detecting the hybridization of the nucleic acid.  
     
     
         36 . An anti-sense nucleotide sequence which hybridizes to the nucleic acid of  claim 15  in a manner that blocks transcription or translation of the nucleic acid.