scholarly journals Raman Spectroscopic Imaging of Cholesterol and Docosahexaenoic Acid Distribution in the Retinal Rod Outer Segment

2011 ◽  
Vol 64 (5) ◽  
pp. 611 ◽  
Author(s):  
Zachary D. Schultz
Keyword(s):  
Docosahexaenoic Acid ◽  
Outer Segment ◽  
Rana Catesbeiana ◽  
Spectroscopic Imaging ◽  
Photoreceptor Cells ◽  
Integral Membrane Protein ◽  
Rod Photoreceptor ◽  
Rod Outer Segment ◽  
Cellular Processes ◽  
Retinal Rod

Raman vibrational spectroscopic imaging was performed on retinal rod cells isolated from bullfrogs (Rana catesbeiana). The Raman spectra enable determination of the lipid and protein rich rod outer segment (ROS) from the nucleus and inner segment of the cell. Peak fitting analysis of spectra obtained from individual rod photoreceptor cells show characteristic vibrational modes that can be associated with cholesterol and docosahexaenoic acid-containing lipids. These results provide direct observations of biomolecular gradients in the rod photoreceptor cells, which, thus far, have been based on indirect detergent extracts and histochemical analysis with indicators such as filipin. The detected biomolecules are associated with regulation of the integral membrane protein rhodopsin, and methods capable of direct observation of these biomolecules offer new routes to exploring their role in the regulation of cellular processes.

scholarly journals Immunocytochemical localization of opsin in the cell membrane of developing rat retinal photoreceptors.

1984 ◽  
Vol 98 (5) ◽  
pp. 1788-1795 ◽  
Author(s):  
I Nir ◽  
D Cohen ◽  
D S Papermaster
Keyword(s):  
Plasma Membrane ◽  
Outer Segment ◽  
Plasma Membranes ◽  
Photoreceptor Cells ◽  
Rod Photoreceptor ◽  
Rod Photoreceptors ◽  
Retinal Photoreceptors ◽  
Retinal Rod ◽  
Ros Formation ◽  
Developing Rat

Mature retinal rod photoreceptors sequester opsin in the disk and plasma membranes of the rod outer segment (ROS). Opsin is synthesized in the inner segment and is transferred to the outer segment along the connecting cilium that joins the two compartments. We have investigated early stages of retinal development during which the polarized distribution of opsin is established in the rod photoreceptor cell. Retinas were isolated from newborn rats, 3-21 d old, and incubated with affinity purified biotinyl-sheep anti-bovine opsin followed by avidin-ferritin. At early postnatal ages prior to the development of the ROS, opsin is labeled by antiopsin on the inner segment plasma membrane. At the fifth postnatal day, as ROS formation begins opsin was detected on the connecting cilium plasma membrane. However, the labeling density of the ciliary plasma membrane was not uniform: the proximal cilium was relatively unlabeled in comparison with the distal cilium and the ROS plasma membrane. In nearly mature rat retinas, opsin was no longer detected on the inner segment plasma membrane. A similar polarized distribution of opsin was also observed in adult human rod photoreceptor cells labeled with the same antibodies. These results suggest that some component(s) of the connecting cilium and its plasma membrane may participate in establishing and maintaining the polarized distribution of opsin.

scholarly journals KINETICS OF ROD OUTER SEGMENT RENEWAL IN THE DEVELOPING MOUSE RETINA

1973 ◽  
Vol 58 (3) ◽  
pp. 650-661 ◽  
Author(s):  
Matthew M. LaVail
Keyword(s):  
Outer Segment ◽  
Photoreceptor Cells ◽  
Mouse Retina ◽  
Rod Photoreceptor ◽  
Adult Level ◽  
Rod Outer Segment ◽  
Equilibrium Length ◽  
Kinetics Of ◽  
Late Stages ◽  
Adult Rate

The kinetics of rod outer segment renewal in the developing retina have been investigated in C57BL/6J mice. Litters of mice were injected with [3H]amino acids at various ages and killed at progressively later time intervals. Plastic 1.5 µm sections of retina were studied by light microscope autoradiography. The rate of outer segment disk synthesis, as judged by labeled disk displacement away from the site of synthesis, is slightly greater than the adult level at 11–13 days of age; it rises to more than 1.6 times the adult rate between days 13 and 17, after which it falls to the adult level at 21–25 days. The rate of disk disposal, as measured by labeled disk movement toward the site of disposal, is less than 15% of the adult level at 11–13 days of age; it rises sharply to almost 70% of the adult level by days 13–15 and then more gradually approaches the adult rate. The net difference in rates of synthesis and disposal accounts for the rapid elongation of rod outer segments in the mouse between days 11 and 17 and the subsequent, more gradual elongation to the adult equilibrium length reached between days 19 and 25. The changing rate of outer segment disk synthesis characterizes the late stages of cytodifferentiation of the rod photoreceptor cells.

Rab6 is associated with a compartment that transports rhodopsin from the trans-Golgi to the site of rod outer segment disk formation in frog retinal photoreceptors

1993 ◽  
Vol 106 (3) ◽  
pp. 803-813 ◽  
Author(s):  
D. Deretic ◽  
D.S. Papermaster
Keyword(s):  
G Proteins ◽  
Outer Segment ◽  
Intracellular Transport ◽  
Integral Membrane Protein ◽  
Sucrose Density Gradient ◽  
Disk Formation ◽  
Rod Outer Segment ◽  
Golgi Vesicles ◽  
Retinal Photoreceptors ◽  
Retinal Rod

The biogenesis of light sensitive membranes in retinal rod photoreceptors involves polarized sorting and targeting of newly synthesized rhodopsin to a specialized domain, the rod outer segment (ROS). We have isolated and characterized the population of post-Golgi membranes that mediate intracellular transport of rhodopsin. In the present study we have examined the association of small (20-25 kDa) GTP-binding (G) proteins with these membranes. We found that one of the small G proteins, rab6, behaves like an integral membrane protein of the post-Golgi vesicles, although approximately 30% of rab6 is soluble. The distribution of the membrane-associated and the soluble forms is highly polarized. By confocal and EM immunocytochemistry it can be seen that most of rab6 is associated with the photoreceptor trans-Golgi cisternae, trans-Golgi network (TGN) and post-Golgi vesicles. The photoreceptor axon and synaptic terminal are unlabeled, but dendrites of deeper retinal layers are labeled. The distribution of rab6 across sucrose density gradient fractions parallels the distribution of sialyltransferase (a TGN marker) activity. About 9% of membrane-bound rab6 is associated, however, with the rhodopsin-bearing sialyltransferase-free post-Golgi vesicles, which represent a very small fraction (< 1%) of the total retinal membranes. Rab6 is absent from the mature ROS disk membranes but it is present at the sites of new ROS disk formation and in the ROS cytoplasm. This suggests that rab6 becomes soluble upon disk membrane formation. Therefore, rab6 may function not only as a component of the sorting machinery of photoreceptors that delivers rhodopsin to its appropriate subcellular domain but may also participate in some aspects of ROS disk morphogenesis.

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.

scholarly journals Biosynthesis and vectorial transport of opsin on vesicles in retinal rod photoreceptors.

1986 ◽  
Vol 34 (1) ◽  
pp. 5-16 ◽  
Author(s):  
D S Papermaster ◽  
B G Schneider ◽  
D DeFoe ◽  
J C Besharse
Keyword(s):  
Plasma Membrane ◽  
Outer Segment ◽  
Photoreceptor Cells ◽  
Disk Surface ◽  
Light Sensitivity ◽  
Apical Plasma Membrane ◽  
Rod Photoreceptor ◽  
Electron Microscopic ◽  
Retinal Rod ◽  
Membrane Bound

Retinal rod photoreceptor cells absorb light at one end and establish synaptic contacts on the other. Light sensitivity is conferred by a set of membrane and cytosol proteins that are gathered at one end of the cell to form a specialized organelle, the rod outer segment (ROS). The ROS is composed of rhodopsin-laden, flattened disk-shaped membranes enveloped by the cell's plasma membrane. Rhodopsin is synthesized on elements of the rough endoplasmic reticulum and Golgi apparatus near the nucleus in the inner segment. From this synthetic site, the membrane-bound apoprotein, opsin, is released from the Golgi in the membranes of small vesicles. These vesicles are transported through the cytoplasm of the inner segment until they reach its apical plasma membrane. At that site, opsin-laden vesicles appear to fuse near the base of the connecting cilium that joins the inner and outer segments. This fusion inserts opsin into the plasma membrane of the photoreceptor. Opsin becomes incorporated into the disk membrane by a process of membrane expansion and fusion to form the flattened disks of the outer segment. Within the disks, opsin is highly mobile, and rapidly rotates and traverses the disk surface. Despite its mobility in the outer segment, quantitative electron microscopic, immunocytochemical, and autoradiographic studies of opsin distribution demonstrate that little opsin is detectable in the inner segment plasma membrane, although its bilayer is in continuity with the plasma membrane of the outer segment. The photoreceptor successfully establishes the polarized distribution of its membrane proteins by restricting the redistribution of opsin after vectorially transporting it to one end of the cell on post-Golgi vesicles.

Guanylate Cyclase of Retinal Rod Outer Segment

1990 ◽  
pp. 139-145
Author(s):  
I. M. Pepe ◽  
I. Panfoli ◽  
C. Cugnoli
Keyword(s):  
Guanylate Cyclase ◽  
Outer Segment ◽  
Rod Outer Segment ◽  
Retinal Rod

Evidence for aerobic metabolism in retinal rod outer segment disks

2009 ◽  
Vol 41 (12) ◽  
pp. 2555-2565 ◽  
Author(s):  
Isabella Panfoli ◽  
Daniela Calzia ◽  
Paolo Bianchini ◽  
Silvia Ravera ◽  
Alberto Diaspro ◽  
...  
Keyword(s):  
Outer Segment ◽  
Aerobic Metabolism ◽  
Rod Outer Segment ◽  
Retinal Rod
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