TY - JOUR
T1 - Arsenic trioxide uptake by human and rat aquaglyceroporins
AU - Liu, Zijuan
AU - Carbrey, Jennifer M.
AU - Agre, Peter
AU - Rosen, Barry P.
N1 - Funding Information:
This work was supported by NIH Grants ES10344 and GM55425 and by a pilot project grant from the Wayne State University Environmental Health Sciences Center in Molecular and Cellular Toxicology With Human Applications to B.P.R. and HL33991, HL48268, and EY11239 to P.A.
PY - 2004/4/16
Y1 - 2004/4/16
N2 - Aquaglyceroporins are channels that allow downhill movement of uncharged solutes such as glycerol and urea. Arsenic trioxide has recently been shown to be translocated by mouse mAQP7 and rat rAQP9. In this study we examined the ability of the four known human members of the aquaglyceroporin family, hAQP3, hAQP7, hAQP9, and hAQP10, to facilitate As(OH)3 movement in Xenopus oocytes. The order of effectiveness as an As(III) transporter was found to be hAQP9hAQP7, with little or no transport by hAQP3 or hAQP10. From comparison with the crystal structure of the bacterial homologue GlpF and the bovine erythrocyte water channel bAQP1, AQP9 residues Phe-64 and Arg-219 are predicted to serve as part of the selectivity filter. The requirement for Phe-64 and Arg-219 in arsenic trioxide translocation was examined by site-directed mutagenesis of rAQP9, taking advantage of the fact that rat AQP9 catalyzes 73As(OH)3 uptake in Saccharomyces cerevisiae and in oocytes. R219A, R219K, F64A, F64T, and F64W were expressed in both yeast and oocytes, and permeability of arsenic trioxide and glycerol was measured. A lysine but not an alanine residue could substitute for the highly conserved Arg-219, indicating that a positive charge is required at the entry to the channel. In contrast, the phenylalanine residue, which is believed to position substrates near the conserved arginine, was not required for either arsenic trioxide or glycerol uptake. The results support the hypothesis that arsenic trioxide and glycerol use the same translocation pathway in AQP9.
AB - Aquaglyceroporins are channels that allow downhill movement of uncharged solutes such as glycerol and urea. Arsenic trioxide has recently been shown to be translocated by mouse mAQP7 and rat rAQP9. In this study we examined the ability of the four known human members of the aquaglyceroporin family, hAQP3, hAQP7, hAQP9, and hAQP10, to facilitate As(OH)3 movement in Xenopus oocytes. The order of effectiveness as an As(III) transporter was found to be hAQP9hAQP7, with little or no transport by hAQP3 or hAQP10. From comparison with the crystal structure of the bacterial homologue GlpF and the bovine erythrocyte water channel bAQP1, AQP9 residues Phe-64 and Arg-219 are predicted to serve as part of the selectivity filter. The requirement for Phe-64 and Arg-219 in arsenic trioxide translocation was examined by site-directed mutagenesis of rAQP9, taking advantage of the fact that rat AQP9 catalyzes 73As(OH)3 uptake in Saccharomyces cerevisiae and in oocytes. R219A, R219K, F64A, F64T, and F64W were expressed in both yeast and oocytes, and permeability of arsenic trioxide and glycerol was measured. A lysine but not an alanine residue could substitute for the highly conserved Arg-219, indicating that a positive charge is required at the entry to the channel. In contrast, the phenylalanine residue, which is believed to position substrates near the conserved arginine, was not required for either arsenic trioxide or glycerol uptake. The results support the hypothesis that arsenic trioxide and glycerol use the same translocation pathway in AQP9.
KW - AQP9
KW - Acute promyelocytic leukemia
KW - Aquaglyceroporin
KW - Arsenic trioxide
KW - Trisenox
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U2 - 10.1016/j.bbrc.2004.03.003
DO - 10.1016/j.bbrc.2004.03.003
M3 - Article
C2 - 15044109
AN - SCOPUS:1642369802
SN - 0006-291X
VL - 316
SP - 1178
EP - 1185
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 4
ER -