Mitogen-activated protein kinase p38-2 and methods of use therefor

Abstract

Compositions and methods are provided for the treatment of diseases associated with mitogen activated protein kinase cascades. In particular, the mitogen-activated protein kinase p38-2, and polypeptide variants thereof that stimulate phosphorylation and activation of substrates such as ATF2, are provided. The polypeptides may be used, for example, to identify antibodies and other agents that inhibit or activate signal transduction via the p38-2 kinase cascade. Such polypeptides and agents may also be used for the treatment of diseases associated with mitogen-activated protein kinase cascades.

1 . A polypeptide comprising an amino acid sequence as recited in SEQ ID NO:2, or a variant thereof that differs only in conservative substitutions and/or modifications at no more than 25% of the amino acid residues.  
     
     
         2 . A constitutively active variant of a polypeptide according to  claim 1 .  
     
     
         3 . A polypeptide comprising the amino acid sequence recited in SEQ ID NO:2, modified at no more than 25% of the amino acid residues, such that said polypeptide is rendered constitutively inactive.  
     
     
         4 . An isolated DNA molecule encoding a polypeptide according to any of claims  1 - 3 .  
     
     
         5 . A DNA molecule according to  claim 4 , wherein the DNA molecule comprises the nucleotide sequence provided in SEQ ID NO:1.  
     
     
         6 . A recombinant expression vector comprising a DNA molecule according to either of claims  4  or  5 .  
     
     
         7 . A host cell transformed or transfected with an expression vector according to  claim 6 .  
     
     
         8 . A host cell according to  claim 7 , wherein the host cell is selected from the group consisting of bacteria, yeast, baculovirus infected insect cells and mammalian cells.  
     
     
         9 . A method for phosphorylating a substrate of p38-2, comprising contacting a polypeptide according to either of claims  1  or  2  with a substrate of p38-2, thereby phosphorylating the substrate of p38-2.  
     
     
         10 . The method of  claim 9 , wherein the substrate of p38-2 is selected from the group consisting of ATF2, MAPKAP kinase 2 and MAPKAP kinase.  
     
     
         11 . A method for activating a substrate of p38-2 in a patient, comprising administering to a patient a polypeptide according to either of claims  1  or  2  in combination with a pharmaceutically acceptable carrier, thereby activating a substrate of p38-2 in the patient.  
     
     
         12 . The method of  claim 11 , wherein the substrate of p38-2 is selected form the group consisting of ATF2, MAPKAP kinase 2 and MAPKAP kinase 3.  
     
     
         13 . A method for screening for an agent that modulates signal transduction via the p38-2 cascade, comprising: 
 (a) contacting a candidate agent with a polypeptide according to either of claims  1  or  2 , wherein the step of contacting is carried out under conditions and for a time sufficient to allow the candidate agent and the polypeptide to interact; and    (b) subsequently measuring the ability of said candidate agent to modulate p38-2 activity, and thereby evaluating the ability of the candidate agent to modulate signal transduction via the p38 cascade.    
     
     
         14 . A method for screening for an agent that modulates signal transduction via the p38-2 cascade, comprising: 
 (a) contacting a candidate agent with a polynucleotide encoding a polypeptide according to either of claims  1  or  2 , wherein the step of contacting is carried out under conditions and for a time sufficient to allow generation of the polypeptide and interaction between the polypeptide and the candidate agent; and    (b) subsequently measuring the ability of said candidate agent to modulate p38-2 activity, and thereby evaluating the ability of the candidate agent to modulate signal transduction via the p38-2 cascade.    
     
     
         15 . An antibody that binds to a polypeptide according to either of claims  1  or  2 .  
     
     
         16 . An antibody according to  claim 15 , wherein said antibody inhibits the phosphorylation of substrate by said polypeptide.  
     
     
         17 . A method for treating a disorder associated with the p38-2 cascade, comprising administering to a patient a therapeutically effective amount of an agent that modulates signal transduction via the p38-2 cascade.  
     
     
         18 . A method for treating a patient afflicted with a disease associated with the p38-2 cascade, comprising administering to a patient an agent that inhibits p38-2 kinase activity.  
     
     
         19 . A method for treating a patient afflicted with a disease associated with the p38-2 cascade, comprising administering to a patient an agent that inhibits phosphorylation of p38-2.  
     
     
         20 . The method of any of claims  17 - 19 , wherein said agent is a monoclonal antibody.  
     
     
         21 . The method of any of claims  17 - 19 , wherein said agent comprises a polynucleotide.  
     
     
         22 . A method for detecting mitogen activated protein kinase kinase activity in a sample, comprising evaluating the ability of the sample to phosphorylate a polypeptide according to either of claims  1  or  2 , thereby detecting mitogen activated protein kinase kinase activity in the sample.  
     
     
         23 . The method of  claim 22 , wherein the mitogen activated protein kinase kinase is MEK6.  
     
     
         24 . The method of  claim 23 , wherein the ability of the sample to phosphorylate a polypeptide is evaluated using a coupled kinase assay.  
     
     
         25 . A kit for detecting mitogen activated protein kinase kinase activity in a sample, comprising p38-2 in combination with a suitable buffer.