help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Roncaglia, P.
Right arrow Articles by Torre, V.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Roncaglia, P.
Right arrow Articles by Torre, V.

Biophys J, October 2002, p. 1953-1964, Vol. 83, No. 4

Pore Topology of the Hyperpolarization-Activated Cyclic Nucleotide-Gated Channel from Sea Urchin Sperm

Paola Roncaglia, Pavel Mistrík, and Vincent Torre

Scuola Internazionale Superiore di Studi Avanzati and Istituto Nazionale di Fisica della Materia Unit, 34014 Trieste, Italy

The current flow through hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, referred to as Ih, plays a major role in several fundamental biological processes. The sequence of the presumed pore region of HCN channels is reminiscent of that of most known K+-selective channels. In the present work, the pore topology of an HCN channel from sea urchin sperm, called SpHCN, was investigated by means of the substituted-cysteine accessibility method (SCAM). The Ih current in the wild-type (w.t.) SpHCN channel was irreversibly blocked by intracellular Cd2+. This blockage was not observed in mutant C428S. Extracellular Cd2+ did not cause any inhibition of the Ih current in the w.t. SpHCN channel, but blocked the current in mutant channels K433C and F434C. Large extracellular anions blocked the current both in the w.t. and K433Q mutant channel. These results suggest that 1) cysteine in position 428 faces the intracellular medium; 2) lysine and phenylalanine in position 433 and 434, respectively, face the extracellular side of the membrane; and 3) lysine 433 does not mediate the anion blockade. Additionally, our study confirms that the K+ channel signature sequence GYG also forms the inner pore in HCN channels.

Biophys J, October 2002, p. 1953-1964, Vol. 83, No. 4
© 2002 by the Biophysical Society   0006-3495/02/10/1953/12  $2.00


This article has been cited by other articles:


Home page
 Am. J. Physiol. Cell Physiol.Home page
S. Vemana, S. Pandey, and H. P. Larsson
Intracellular Mg2+ is a voltage-dependent pore blocker of HCN channels
Am J Physiol Cell Physiol, August 1, 2008; 295(2): C557 - C565.
[Abstract] [Full Text] [PDF]

Home page
 J. Gen. Physiol.Home page
D. L. Prole and G. Yellen
Reversal of HCN Channel Voltage Dependence via Bridging of the S4-S5 Linker and Post-S6
J. Gen. Physiol., August 28, 2006; 128(3): 273 - 282.
[Abstract] [Full Text] [PDF]

Home page
 J. Gen. Physiol.Home page
C. Proenza and G. Yellen
Distinct Populations of HCN Pacemaker Channels Produce Voltage-dependent and Voltage-independent Currents
J. Gen. Physiol., January 30, 2006; 127(2): 183 - 190.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
A. Giorgetti, P. Carloni, P. Mistrik, and V. Torre
A Homology Model of the Pore Region of HCN Channels
Biophys. J., August 1, 2005; 89(2): 932 - 944.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
D. Bichet, Y.-F. Lin, C. A. Ibarra, C. S. Huang, B. A. Yi, Y. N. Jan, and L. Y. Jan
Evolving potassium channels by means of yeast selection reveals structural elements important for selectivity
PNAS, March 30, 2004; 101(13): 4441 - 4446.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2002 by the Biophysical Society.