Sodium-independent small neutral amino acid transporter transporting L- and D- amino acids

Abstract

Novel sodium-independent small neutral amino acid transporters which transport L- and D-amino acids. A protein comprising the amino acid sequence represented by SEQ ID NO:1 or 4 or an amino acid derived therefrom by deletion, substitution or addition of one or more amino acids and being capable of sodium-independently transporting L- and D-small neutral amino acids and analogs thereof; a gene encoding the above protein; a method of screening substances inhibiting or promoting the function of the above protein; an antibody against the above protein; and a method of regulating cell function by using the above antibody, function inhibitors, function promoters, etc.

1 .- 14 . (canceled)  
     
     
         15 . A method for detection, identification or quantification of action as a substrate of a substance to be tested to the ability of transporting a small neutral amino acid and analogs thereof in a sodium-independent manner using a protein which comprises an amino acid sequence represented by SEQ ID NO: 1 or 4 or an amino acid sequence where one or more amino acid(s) is/are deleted, substituted or added in the said amino acid sequence and which is capable of transporting a small neutral amino acid or analog thereof in a sodium-independent manner.  
     
     
         16 .- 22 . (canceled)  
     
     
         23 . The method of  claim 15 , wherein the protein is derived from human being or from mouse.  
     
     
         24 . The method of  claim 15 , wherein the protein is derived from orphan, tissue or cultured cell.  
     
     
         25 . A method for determining whether a test substance is a substrate for a protein which comprises an amino acid sequence represented by SEQ ID NO: 1 or 4 or an amino acid sequence where one or more amino acid(s) is/are deleted, substituted or added in the said amino acid sequence and which is capable of transporting a small neutral amino acid or analog thereof in a sodium-independent manner, the method comprising the step of contacting the protein with the test substance, and determining whether the test substance is a substrate for the protein.