Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-25T06:12:26.935Z Has data issue: false hasContentIssue false
  • English
  • Français

The cGMP-gated channel of photoreceptor cells: Its structural properties and role in phototransduction

Published online by Cambridge University Press:  04 February 2010

Robert S. Molday  and
Yi-Te Hsu
Robert S. Molday
Affiliation:
Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3 Electronic mail: [email protected]
Yi-Te Hsu
Affiliation:
Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3
Get access Rights & Permissions [Opens in a new window]

Abstract

The cyclic GMP-gated channel responds to changes in free intracellular cGMP, and as a result, it plays a central role in the phototransduction process in rod and cone photoreceptor cells. Recent biochemical, immunochemical, and molecular biology studies indicate that this channel consists of a complex of two distinct subunits and one or more associated proteins. Primary structural analysis indicates that the a and (3 subunits contain a cGMP-binding domain, an even number of membrane-spanning segments, a voltage sensor motif and a pore region. The latter two features are found in voltage-gated channels and suggest that these two classes of channels have evolved from the same ancestral channel protein. A working model for the membrane topography of the channel subunits is proposed based on immunogold labeling studies and sequence analysis. Recent studies also indicate that calmodulin binds to the 240 kDa protein of the channel complex and modulates the sensitivity of the channel for cGMP in a Ca2+-dependent manner. The molecular properties of the channel complex and the possible role of Ca2+-calmodulin modulation of the channel during photoactivation and photorecovery are discussed in relation to the current mechanism of phototransduction in photoreceptor cells

Keywords

calmodulincGMP-gated channelphotorecoveryphototransductionrod photoreceptor cells
Type
Research Article
Information
Behavioral and Brain Sciences , Volume 18 , Special Issue 3: An International Journal of Current Research and Theory with Open Peer Commentary , September 1995 , pp. 441 - 451
Copyright
Copyright © Cambridge University Press 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)