TY - JOUR
T1 - Functional characterization of the human multidrug transporter, ABCG2, expressed in insect cells
AU - Ozvegy, C
AU - Litman, Thomas
AU - Szakács, G
AU - Nagy, Z
AU - Bates, S
AU - Váradi, A
AU - Sarkadi, B
N1 - Copyright 2001 Academic Press.
PY - 2001/7/6
Y1 - 2001/7/6
N2 - ABCG2 (also called MXR (3), BCRP (4), or ABCP (5) is a recently-identified ABC half-transporter, which causes multidrug resistance in cancer. Here we report that the expression of the ABCG2 protein in Sf9 insect cells resulted in a high-capacity, vanadate-sensitive ATPase activity in isolated membrane preparations. ABCG2 was expressed underglycosylated, and its ATPase activity was stimulated by daunorubicin, doxorubicin, mitoxantrone, prazosin and rhodamine 123, compounds known to be transported by this protein. ABCG2-ATPase was inhibited by low concentrations of Na-orthovanadate, N-ethylmaleimide and cyclosporin A. Verapamil had no effect, while Fumitremorgin C, reversing ABCG2-dependent cancer drug resistance, strongly inhibited this ATPase activity. The functional expression of ABCG2 in this heterologous system indicates that no additional partner protein is required for the activity of this multidrug transporter, probably working as a homodimer. We suggest that the Sf9 cell membrane ATPase system is an efficient tool for examining the interactions of ABCG2 with pharmacological agents.
AB - ABCG2 (also called MXR (3), BCRP (4), or ABCP (5) is a recently-identified ABC half-transporter, which causes multidrug resistance in cancer. Here we report that the expression of the ABCG2 protein in Sf9 insect cells resulted in a high-capacity, vanadate-sensitive ATPase activity in isolated membrane preparations. ABCG2 was expressed underglycosylated, and its ATPase activity was stimulated by daunorubicin, doxorubicin, mitoxantrone, prazosin and rhodamine 123, compounds known to be transported by this protein. ABCG2-ATPase was inhibited by low concentrations of Na-orthovanadate, N-ethylmaleimide and cyclosporin A. Verapamil had no effect, while Fumitremorgin C, reversing ABCG2-dependent cancer drug resistance, strongly inhibited this ATPase activity. The functional expression of ABCG2 in this heterologous system indicates that no additional partner protein is required for the activity of this multidrug transporter, probably working as a homodimer. We suggest that the Sf9 cell membrane ATPase system is an efficient tool for examining the interactions of ABCG2 with pharmacological agents.
KW - ATP-Binding Cassette Transporters
KW - Adenosine Triphosphatases
KW - Animals
KW - Breast Neoplasms
KW - Cell Membrane
KW - Cloning, Molecular
KW - Drug Resistance, Multiple
KW - Drug Resistance, Neoplasm
KW - Humans
KW - Neoplasm Proteins
KW - Recombinant Proteins
KW - Spodoptera
KW - Tumor Cells, Cultured
U2 - 10.1006/bbrc.2001.5130
DO - 10.1006/bbrc.2001.5130
M3 - Journal article
C2 - 11437380
SN - 0006-291X
VL - 285
SP - 111
EP - 117
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 1
ER -
