Expression of rat renal sulfate transport systems in Xenopus laevis oocytes. Functional characterization and molecular identification.
Renal proximal tubular sulfate reabsorption is mediated by brush border membrane Na+/sulfate-cotransport and basolateral Na(+)-independent sulfate transport. Injection of rat kidney cortex mRNA into Xenopus laevis oocytes induced Na(+)-dependent as well as Na(+)-independent sulfate transport. The inhibition pattern of Na(+)-dependent uptake coincided with that known for the brush border membrane; the inhibition pattern of Na(+)-independent uptake suggested that this activity could be related to the basolateral cell surface. By Northern blot hybridization of size-fractionated mRNA, we provide evidence that the Na(+)-dependent uptake is induced by an mRNA species related to a recently cloned cDNA encoding rat renal cortex Na+/SO4 cotransport (NaSi-1; Markovich, D., Forgo, J., Stange, G., Biber, J., and Murer, H. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 8073-8077); the Na(+)-independent sulfate transport activity seems to be related to an mRNA species encoding a rat liver Na(+)-independent sulfate transporter (Bissig, M., Hagenbuch, B., Stieger, B., Koller, T., and Meier, P. J. (1994) J. Biol. Chem. 269, 3017-3021). Hybrid depletion experiments using antisense oligonucleotides provided further evidence for the association of the expressed transport activities to NaSi-1 and sat-1, respectively.
Markovich
D
D
Institute of Physiology, University of Zürich, Switzerland.
Bissig
M
M
Sorribas
V
V
Hagenbuch
B
B
Meier
P J
PJ
Murer
H
H
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D001693:Biological Transport, Active / Q000187:drug effects; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000378:metabolism; D005260:Female; D007672:Kidney Cortex / Q000378:metabolism*; D007700:Kinetics; D026901:Membrane Transport Proteins; D008871:Microvilli / Q000378:metabolism; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000378:metabolism; D000076988:Sulfate Transporters; D013431:Sulfates / Q000378:metabolism*; D013885:Thiosulfates / Q000494:pharmacology; D014982:Xenopus laevis
D002352:Carrier Proteins; D026901:Membrane Transport Proteins; D009838:Oligodeoxyribonucleotides; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters; D013431:Sulfates; D013885:Thiosulfates; D012964:Sodium; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid