Phosphoprotein target for insulin and its antagonists

Abstract

This invention provides methods for diagnosing and treating individuals with insulin resistance.

1 . A method for diagnosing insulin resistance in an individual comprising obtaining a biological sample from the individual and determining a level of at least one of P20 isoforms S2 and S3, wherein the individual is diagnosed as being insulin resistant when the level of expression of at least one of S2 and S3 is higher than a reference level characteristic of an individual not suffering from insulin resistance.  
     
     
         2 . The method according to  claim 1  wherein the cells in the biological sample are contacted with insulin ex vivo.  
     
     
         3 . The method according to  claim 1  wherein the levels of both S2 and S3 are determined.  
     
     
         4 . The method according to  claim 3  wherein the levels of both S2 and S3 are higher than a reference level characteristic of an individual not suffering from insulin resistance.  
     
     
         5 . A method for diagnosing insulin resistance or a propensity to insulin resistance in an individual comprising determining the level of expression of at least one of P20 isoforms S2 and S3 in a cell of an individual, and comparing the level to a reference level characteristic of a cell of the same type in an individual not suffering from insulin resistance or diabetes wherein a level of expression that is higher than the reference level is diagnostic of insulin resistance or a propensity to insulin resistance in the individual.  
     
     
         6 . The method of  claim 5  wherein the levels of both S2 and S3 are determined.  
     
     
         7 . The method of  claim 6  wherein the levels of both S2 and S3 are higher than the reference level.  
     
     
         8 . The method of  claim 5  wherein the level of expression of S2 and/or S3 is the same as greater than a second reference level, wherein said second reference level is characteristic of an individual with insulin resistance.  
     
     
         9 . A method of assessing the efficacy of a treatment for insulin resistance in an individual comprising monitoring the level of at least one of S2 and S3 in the individual to whom the treatment has been administered.  
     
     
         10 . A method of treating insulin resistance in an individual comprising administering a treatment or an agent that reduces the level of P20 isoforms S2 and S3 in the individual.  
     
     
         11 . The method according to  claim 10  wherein the agent is identified by a method for screening for an agent useful for treatment of insulin resistance comprising contacting a mammalian cell expressing P20 and the agent and determining if the agent suppresses the level of at least one of P20 isoforms S2 and S3, wherein the suppression of S2 and S3 levels is indicative of an agent useful for treatment of insulin resistance.