Rapid calcium release and proton uptake at the disk membrane of isolated cattle rod outer segments. 1. Stoichiometry of light-stimulated calcium release and proton uptake

Biochemistry ◽  
1981 ◽  
Vol 20 (19) ◽  
pp. 5500-5510 ◽  
Author(s):  
U. B. Kaupp ◽  
P. P. M. Schnetkamp ◽  
W. Junge
Keyword(s):  
Calcium Release ◽  
Rod Outer Segments ◽  
Outer Segments ◽  
Disk Membrane ◽  
Proton Uptake

scholarly journals Localization of peripherin/rds in the disk membranes of cone and rod photoreceptors: relationship to disk membrane morphogenesis and retinal degeneration.

1992 ◽  
Vol 116 (3) ◽  
pp. 659-667 ◽  
Author(s):  
K Arikawa ◽  
L L Molday ◽  
R S Molday ◽  
D S Williams
Keyword(s):  
Plasma Membrane ◽  
Retinal Degeneration ◽  
Outer Segment ◽  
Photoreceptor Cells ◽  
Growth Stages ◽  
Rod Outer Segments ◽  
Rod Photoreceptor ◽  
Outer Segments ◽  
Disk Membrane ◽  
Membrane Morphogenesis

The outer segments of vertebrate rod photoreceptor cells consist of an ordered stack of membrane disks, which, except for a few nascent disks at the base of the outer segment, is surrounded by a separate plasma membrane. Previous studies indicate that the protein, peripherin or peripherin/rds, is localized along the rim of mature disks of rod outer segments. A mutation in the gene for this protein has been reported to be responsible for retinal degeneration in the rds mouse. In the present study, we have shown by immunogold labeling of rat and ground squirrel retinas that peripherin/rds is present in the disk rims of cone outer segments as well as rod outer segments. Additionally, in the basal regions of rod and cone outer segments, where disk morphogenesis occurs, we have found that the distribution of peripherin/rds is restricted to a region that is adjacent to the cilium. Extension of its distribution from the cilium coincides with the formation of the disk rim. These results support the model of disk membrane morphogenesis that predicts rim formation to be a second stage of growth, after the first stage in which the ciliary plasma membrane evaginates to form open nascent disks. The results also indicate how the proteins of the outer segment plasma membrane and the disk membranes are sorted into their separate domains: different sets of proteins may be incorporated into membrane outgrowths during different growth stages of disk morphogenesis. Finally, the presence of peripherin/rds protein in both cone and rod outer segment disks, together with the phenotype of the rds mouse, which is characterized by the failure of both rod and cone outer segment formation, suggest that the same rds gene is expressed in both types of photoreceptor cells.

scholarly journals Correlation of rhodopsin biogenesis with ultrastructural morphogenesis in the chick retina.

1975 ◽  
Vol 64 (1) ◽  
pp. 235-241 ◽  
Author(s):  
W T Mason ◽  
K J Bighouse
Keyword(s):  
Outer Segment ◽  
Receptor Cell ◽  
Rod Outer Segments ◽  
Membrane Biogenesis ◽  
Rod Outer Segment ◽  
Rods And Cones ◽  
Outer Segments ◽  
Chick Retina ◽  
Disk Membrane ◽  
Detergent Extraction

The developing chick retina from stages 39-45 has been examined by biochemical and electron microscope techniques. The levels of rhodopsin contained in the maturing chick retina were evaluated by detergent extraction and correlated with rod outer segment formation. It was found that the appearance of rhodopsin in significant levels preceded outer segment formation by at least 2 days, thus implying that rhodopsin is synthesized in the receptor cell inner segment and translocated to the outer limb when disk membrane biogenesis occurs. The level of rhodopsin continues to rise as the rod outer segment develops. Development of both rods and cones originates and proceeds most rapidly in the fundus or central region and proceeds toward the periphery. In general, rod outer segments were noted to develop far more rapidly than cone outer segments.

Proton Uptake by Light Induced Interaction between Rhodopsin and G-Protein

1985 ◽  
Vol 40 (5-6) ◽  
pp. 400-405 ◽  
Author(s):  
Andreas Schleicher ◽  
Klaus Peter Hofmann
Keyword(s):  
G Protein ◽  
Outer Segment ◽  
Bromocresol Purple ◽  
Rod Outer Segments ◽  
Rod Outer Segment ◽  
Outer Segments ◽  
Proton Uptake ◽  
Indicator Dye ◽  
Ph Electrode

Abstract The light-induced proton uptake of rod outer segment disc membranes has been investigated in the absence and presence of G-protein. Proton uptake was measured as the alkalisation of the suspending medium using a pH electrode and/or the indicator dye bromocresol purple. It was found that besides the known proton uptake of photolysed rhodopsin additional uptake of one proton accompanies formation of the complex between rhodopsin and G-protein. No measurable proton uptake was found under conditions of rapid redissociation of the complex indicating an only transient protonation during its lifetime. Proton uptake was the same in washed membra­nes recombined with G-protein and in ordinarily stacked rod outer segments. The additional proton uptake reported here is not due to enhanced metarhodopsin II.

scholarly journals Surfaces of rod photoreceptor disk membranes: light-activated enzymes.

1982 ◽  
Vol 95 (2) ◽  
pp. 501-509 ◽  
Author(s):  
D J Roof ◽  
J I Korenbrot ◽  
J E Heuser
Keyword(s):  
Particle Density ◽  
Rod Outer Segments ◽  
Rod Photoreceptor ◽  
Outer Segments ◽  
Cytoplasmic Surface ◽  
Bright Flash ◽  
Large Particles ◽  
Disk Membrane ◽  
Rule Out ◽  
Number Of Particles

The light-activated GTP-binding protein (GBP) in toad rod outer segments has been located on the cytoplasmic surface (CS) of rod disk membranes by correlating biochemical results with images of quick-frozen, freeze-fractured, and deep-etched rod outer segments. This has been accomplished by selectively removing and replacing the 8-12-nm particles that are found on the CS of disk membranes, exactly in parallel with the GBP. In contrast, the large particles are not correlated with another major disk enzyme, the light-activated cGMP phosphodiesterase. We have been unable to visualize this protein. The surface density of large particles, one particle per eleven rhodopsins in isolated rod outer segments and one particle per nine rhodopsins in intact retina, correlates well with previous biochemical estimates of GBP numbers based on enzyme activity. After the identification of the large particles, we tested the effects of light on the density of particles on the surface of disk membranes in intact retinas. Retinas quick-frozen at various intervals after a bright flash of light show a modest increase (approximately 30%) in particle density by 10 s after the flash but no increase before 1 s. The number of particles on the disk membrane returns to dark levels between 1 and 10 min after the flash. The 1-s latency in the change of particle binding would appear to rule out this process as a mechanism for initiating phototransduction in the rod.

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