|
|
||||||||
Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322-3030
Heterologous expression of a variety of membrane proteins in Xenopus oocytes sometimes results in the appearance of a hyperpolarization-activated inward current. The nature of this current remains incompletely understood. Some investigators have suggested that this current is a Cl current, whereas others have identified it as a nonselective cation current. The purpose of this investigation was to characterize this current in more detail. The hyperpolarization-activated inward current (IIN) present in native oocytes was composed of a current carried at least partly by Ca and Mg under physiological ionic conditions plus a Ca-activated Cl current. The Ca-activated Cl current was blocked by chelation of cytosolic Ca with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. When Cl currents were blocked, the cation current could be carried by Ca, Mg, or Co, but not appreciably by Ba, Mn, or Cd. IIN was stimulated by intracellular acidification. The properties of IIN were quite different from those of the store-operated Ca current. Heterologous expression of transient receptor potential-like gene product (TRPL), one of the members of the transient receptor potential family of putative store-operated Ca channels, apparently resulted in alteration of the voltage sensitivity of the endogenous IIN.
chloride current; magnesium; divalent cation; D-myo-inositol 1,4,5-trisphosphate; calcium chelator
This article has been cited by other articles:
![]() |
H. Guizouarn, S. Martial, N. Gabillat, and F. Borgese Point mutations involved in red cell stomatocytosis convert the electroneutral anion exchanger 1 to a nonselective cation conductance Blood, September 15, 2007; 110(6): 2158 - 2165. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Qu, R. Fischmeister, and C. Hartzell Mouse Bestrophin-2 Is a Bona fide Cl- Channel: Identification of a Residue Important in Anion Binding and Conduction J. Gen. Physiol., March 29, 2004; 123(4): 327 - 340. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. G. Goss, L. Jiang, D. H. Vandorpe, D. Kieller, M. N. Chernova, M. Robertson, and S. L. Alper Role of JNK in hypertonic activation of Cl--dependent Na+/H+ exchange in Xenopus oocytes Am J Physiol Cell Physiol, December 1, 2001; 281(6): C1978 - C1990. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. H. Vandorpe, S. Wilhelm, L. Jiang, O. Ibraghimov-Beskrovnaya, M. N. Chernova, A. K. Stuart-Tilley, and S. L. Alper Cation channel regulation by COOH-terminal cytoplasmic tail of polycystin-1: mutational and functional analysis Physiol Genomics, February 28, 2002; 8(2): 87 - 98. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |