Modified proteins, isolated novel peptides,and uses thereof

摘要

The present invention provides several modified ABC transporter polypeptides that exhibit novel localization in the plasma membrane of polarized and non-polarized cells. The modified ABC transporter of the invention comprises the amino acid sequence of a native apically targeted ABC transporter, in particular cMOAT, MDR3 or MRP4, wherein the terminal tripeptide T-K-F motif of said native ABC transporter is mutated. The isolated modified ABC transporter polypeptide of the invention, and the nucleotide sequence encoding said polypeptide, have utility in the following applications: First, they are used to induce a drug resistant phenotype in a cell. Second, they are used to protect non-polarized cells during chemotherapy and other therapeutic applications. Third, they are used to produce novel cell lines that are used to screen for novel agonists or antagonists of the corresponding native ABC transporter polypeptides.