Definitions of P Glycoproteins

  1. A subfamily of transmembrane proteins from the superfamily of ATP- BINDING CASSETTE TRANSPORTERS that are closely related in sequence to P- GLYCOPROTEIN. When overexpressed, they function as ATP- dependent efflux pumps able to extrude lipophilic drugs, especially ANTINEOPLASTIC AGENTS, from cells causing multidrug resistance ( DRUG RESISTANCE, MULTIPLE). Although P- Glycoproteins share functional similarities to MULTIDRUG RESISTANCE- ASSOCIATED PROTEINS they are two distinct subclasses of ATP- BINDING CASSETTE TRANSPORTERS, and have little sequence homology.