Voltage dependence of -arginine transport by hCAT-2A and hCAT-2B expressed in oocytes from

Nawrath H, Wegener J, Rupp J, Habermeier A, Closs EI (2000)
American Journal of Physiology-Cell Physiology 279(5): C1336-C1344.

Zeitschriftenaufsatz | Veröffentlicht | Englisch
 
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Autor*in
Nawrath, Hermann; Wegener, JörgUniBi ; Rupp, Johanna; Habermeier, Alice; Closs, Ellen I.
Abstract / Bemerkung
Membrane potential and currents were investigated with the two-electrode voltage-clamp technique in Xenopus laevisoocytes expressing hCAT-2A or hCAT-2B, the splice variants of the human cationic amino acid transporter hCAT-2. Both hCAT-2A- and hCAT-2B-expressing oocytes exhibited a negative extracellularl-arginine concentration ([l-Arg]o)-sensitive membrane potential, additive to the K+diffusion potential, when cells were incubated in Leibovitz medium (containing 1.45 mM l-Arg and 0.25 mM l-lysine). The two carrier proteins produced inward and outward currents, which were dependent on the l-Arg gradient and membrane potential. Ion substitution experiments showed that the hCAT-induced currents were independent of external Na+, K+, Ca2+, or Mg2+. The apparent Michaelis-Menten constant values at −60 mV, obtained from plots of l-Arg-induced currents against [l-Arg]o, were 0.97 and 0.13 mM in oocytes expressing hCAT-2A and hCAT-2B, respectively; maximal currents amounted to −194 ± 8 and −84 ± 2 nA, respectively. At saturating [l-Arg]o, the current-voltage relationships of hCAT-2A-expressing oocytes became steeper, yielding an additional conductance up to 2 μS/oocyte, whereas those of hCAT-2B-expressing oocytes were simply shifted to the right, resulting in voltage-independent difference currents. The distinct electrochemical properties of the two isoforms of hCAT-2 are assumed to contribute differentially to the membrane transport and the maintenance of cationic amino acids in various tissues.
Erscheinungsjahr
2000
Zeitschriftentitel
American Journal of Physiology-Cell Physiology
Band
279
Ausgabe
5
Seite(n)
C1336-C1344
ISSN
0363-6143
eISSN
1522-1563
Page URI
https://pub.uni-bielefeld.de/record/2984505

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Nawrath H, Wegener J, Rupp J, Habermeier A, Closs EI. Voltage dependence of -arginine transport by hCAT-2A and hCAT-2B expressed in oocytes from. American Journal of Physiology-Cell Physiology. 2000;279(5):C1336-C1344.
Nawrath, H., Wegener, J., Rupp, J., Habermeier, A., & Closs, E. I. (2000). Voltage dependence of -arginine transport by hCAT-2A and hCAT-2B expressed in oocytes from. American Journal of Physiology-Cell Physiology, 279(5), C1336-C1344. https://doi.org/10.1152/ajpcell.2000.279.5.C1336
Nawrath, Hermann, Wegener, Jörg, Rupp, Johanna, Habermeier, Alice, and Closs, Ellen I. 2000. “Voltage dependence of -arginine transport by hCAT-2A and hCAT-2B expressed in oocytes from”. American Journal of Physiology-Cell Physiology 279 (5): C1336-C1344.
Nawrath, H., Wegener, J., Rupp, J., Habermeier, A., and Closs, E. I. (2000). Voltage dependence of -arginine transport by hCAT-2A and hCAT-2B expressed in oocytes from. American Journal of Physiology-Cell Physiology 279, C1336-C1344.
Nawrath, H., et al., 2000. Voltage dependence of -arginine transport by hCAT-2A and hCAT-2B expressed in oocytes from. American Journal of Physiology-Cell Physiology, 279(5), p C1336-C1344.
H. Nawrath, et al., “Voltage dependence of -arginine transport by hCAT-2A and hCAT-2B expressed in oocytes from”, American Journal of Physiology-Cell Physiology, vol. 279, 2000, pp. C1336-C1344.
Nawrath, H., Wegener, J., Rupp, J., Habermeier, A., Closs, E.I.: Voltage dependence of -arginine transport by hCAT-2A and hCAT-2B expressed in oocytes from. American Journal of Physiology-Cell Physiology. 279, C1336-C1344 (2000).
Nawrath, Hermann, Wegener, Jörg, Rupp, Johanna, Habermeier, Alice, and Closs, Ellen I. “Voltage dependence of -arginine transport by hCAT-2A and hCAT-2B expressed in oocytes from”. American Journal of Physiology-Cell Physiology 279.5 (2000): C1336-C1344.
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