Light-suppressible, cyclic GMP-sensitive conductance in the plasma membrane of a truncated rod outer segment

Nature ◽  
1985 ◽  
Vol 317 (6034) ◽  
pp. 252-255 ◽  
Author(s):  
King-Wai Yau ◽  
Kei Nakatani
Keyword(s):  
Plasma Membrane ◽  
Cyclic Gmp ◽  
Outer Segment ◽  
Rod Outer Segment

Induction by cyclic GMP of cationic conductance in plasma membrane of retinal rod outer segment

Nature ◽  
1985 ◽  
Vol 313 (6000) ◽  
pp. 310-313 ◽  
Author(s):  
Evgeniy E. Fesenko ◽  
Stanislav S. Kolesnikov ◽  
Arkadiy L. Lyubarsky
Keyword(s):  
Plasma Membrane ◽  
Cyclic Gmp ◽  
Outer Segment ◽  
Rod Outer Segment ◽  
Retinal Rod

scholarly journals The effect of the γ-subunit of the cyclic GMP phosphodiesterase of bovine and frog (Rana catesbiana) retinal rod outer segments on the kinetic parameters of the enzyme

1990 ◽  
Vol 265 (3) ◽  
pp. 655-658 ◽  
Author(s):  
M M Whalen ◽  
M W Bitensky ◽  
D J Takemoto
Keyword(s):  
Catalytic Activity ◽  
Cyclic Gmp ◽  
Active Sites ◽  
Outer Segment ◽  
Maximal Activity ◽  
Inhibitory Effect ◽  
Gamma Subunit ◽  
Rod Outer Segment ◽  
Gamma Subunits ◽  
Alpha Beta

Rod-outer-segment cyclic GMP phosphodiesterase (PDE) (subunit composition alpha beta gamma 2) contains catalytic activity in alpha beta. The gamma-subunits are inhibitors. Removal of the gamma-subunits increases Vmax. without affecting the Km. The inhibitory effect of a single gamma-subunit (alpha beta gamma) on the Vmax. of alpha beta is much greater in bovine than in frog (Rana catesbiana) PDE. Bovine PDE in the alpha beta gamma 2 state has a Vmax. that is 2.6 +/- 0.4% of the Vmax. of alpha beta. The removal of one gamma-subunit to give alpha beta gamma results in a Vmax. 5.2 +/- 1% of that for maximal activity. Frog alpha beta gamma 2 has a Vmax. 10.8 +/- 2%, and alpha beta gamma has a Vmax. 50 +/- 18%, of the Vmax. of alpha beta. These data suggest that a single gamma-subunit can inhibit the catalytic activity of active sites on both alpha- and beta-subunits in bovine, but not in frog, rod-outer-segment PDE.

scholarly journals Structural and functional characterization of the rod outer segment membrane guanylate cyclase

1994 ◽  
Vol 302 (2) ◽  
pp. 455-461 ◽  
Author(s):  
R M Goraczniak ◽  
T Duda ◽  
A Sitaramayya ◽  
R K Sharma
Keyword(s):  
Cyclic Gmp ◽  
Outer Segment ◽  
Photoreceptor Cell ◽  
Functional Characterization ◽  
Visual Signal ◽  
Membrane Guanylate Cyclase ◽  
Rod Outer Segment ◽  
Vertebrate Photoreceptor ◽  
Hydrolysis Of

In the vertebrate photoreceptor cell, rod outer segment (ROS) is the site of visual signal-transduction process, and a pivotal molecule that regulates this process is cyclic GMP. Cyclic GMP controls the cationic conductance into the ROS, and light causes a decrease in the conductance by activating hydrolysis of the cyclic nucleotide. The identity of the granylate cyclase (ROS-GC) that synthesizes this pool of cyclic GMP is unknown. We now report the cloning, expression and functional characterization of a DNA from bovine retina that encodes ROS-GC.

Rod outer segment phosphodiesterase: Factors affecting the hydrolysis of cyclic-AMP and cyclic-GMP

1974 ◽  
Vol 18 (6) ◽  
pp. 509-515 ◽  
Author(s):  
G. Chader ◽  
R. Fletcher ◽  
M. Johnson ◽  
R. Bensinger
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Outer Segment ◽  
Factors Affecting ◽  
Rod Outer Segment ◽  
Hydrolysis Of

scholarly journals A derivative of amiloride blocks both the light-regulated and cyclic GMP-regulated conductances in rod photoreceptors.

1987 ◽  
Vol 90 (5) ◽  
pp. 651-669 ◽  
Author(s):  
G D Nicol ◽  
P P Schnetkamp ◽  
Y Saimi ◽  
E J Cragoe ◽  
M D Bownds
Keyword(s):  
Plasma Membrane ◽  
Cyclic Gmp ◽  
Dark Current ◽  
Outer Segment ◽  
Light Response ◽  
Ionic Channels ◽  
Rod Photoreceptors ◽  
Low Concentrations ◽  
Excised Patches ◽  
Activated Flux

Vertebrate rod photoreceptors in the dark maintain an inward current across the outer segment membrane. The photoresponse results from a light-induced suppression of this dark current. The light-regulated current is not sensitive to either tetrodotoxin or amiloride, potent blockers of Na+ channels. Here, we report that a derivative of amiloride, 3',4'-dichlorobenzamil (DCPA), completely suppresses the dark current and light response recorded from rod photoreceptors. DCPA also blocks a cyclic GMP-activated current in excised patches of rod plasma membrane and a cGMP-induced Ca++ flux from rod disk membranes. These results are consistent with the notion that the Ca++ flux mechanism in the disk membrane and the light-regulated conductance in the plasma membrane are identical. DCPA also inhibits the Na/Ca exchange mechanism in intact rods, but at a 5-10-fold-higher concentration than is required to block the cGMP-activated flux and current. The blocking action of DCPA in 10 nM Ca++ is different from that in 1 mM Ca++, which suggests either that the conductance state of the light-regulated channel may be modified in high and low concentrations of Ca++, or that there may be two ionic channels in the rod outer segment membrane.

Tubulin in bovine retinal rod outer segments

1992 ◽  
Vol 103 (1) ◽  
pp. 157-166
Author(s):  
D.F. Matesic ◽  
N.J. Philp ◽  
J.M. Murray ◽  
P.A. Liebman
Keyword(s):  
Plasma Membrane ◽  
Outer Segment ◽  
Photoreceptor Cells ◽  
High Salt ◽  
Immunofluorescent Staining ◽  
Rod Outer Segments ◽  
Rod Outer Segment ◽  
Retinal Rod ◽  
Additional Role ◽  
Retinal Rod Outer Segments

Bovine rod outer segment (ROS) preparations contain a major 58 kDa protein doublet that was identified by immunoblot as tubulin. Quantification by gel densitometry showed that the total amount of tubulin was 5- to 10-fold higher than that attributable to the rod axoneme, suggesting additional role(s) for tubulin in photoreceptor cells. Approximately 20% of this nonaxonemal tubulin (15% of total tubulin) is tightly associated with outer segment membranes. This fraction remains membrane-associated after extensive low- or high-salt washing, requiring detergents or protein denaturants for release from ROS membranes. Unlike ROS soluble tubulin it associates tightly with liposomes upon detergent solubilization and reconstitution. The ROS membrane-associated tubulin is highly enriched in isolated ROS plasma membrane fractions compared to the total outer segment membrane pool and can be localized to the plasma membrane but not to disks by immunofluorescent staining, suggesting a possible role in the structure or electrophysiology of the rod outer segment plasma membrane.

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