Insect cell versus bacterial overexpressed membrane proteins: an example, the human ABCG2 transporter.
The multidrug resistance phenotype of cancer cells has been often related to overexpression of plasma membrane ATP-binding cassette transporters, which are able to efflux many types of drug by using the energy of ATP hydrolysis. ABCG2 is a half-transporter recently involved. Its purification would help to understand the mechanism of both transport and its inhibition. Biophysical, structural, and functional studies are consuming great amounts of homogeneous purified proteins and require efficient overexpression systems. Heterologous overexpression of human membrane proteins is actually a challenge because these proteins are toxic for the host, and both translation and chaperone systems of the host are not well adapted to the biosynthesis of human proteins. Overexpression of ABCG2 has been assayed in both bacterial and insect cell/baculovirus systems. Although it was highly overexpressed in bacterial system, neither transport nor ATPase activity was found within inverted membrane vesicles. By contrast, insect cells/baculovirus system produces a low amount of protein, a part of which is active.
Pozza
Alexandre
A
Institut de Biologie et Chimie des Protéines, UMR5086 CNRS-Université Lyon 1 et IFR128 BioSciences Gerland, Lyon, France.
Pérez-Victoria
José M
JM
Di Pietro
Attilio
A
D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D016367:Baculoviridae / Q000235:genetics*; D002460:Cell Line; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005822:Genetic Vectors / Q000235:genetics*; D006801:Humans; D016297:Mutagenesis, Site-Directed; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D018411:Spodoptera
C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D009363:Neoplasm Proteins