OUTER SEGMENT RENEWAL IN PHOTORECEPTOR CELLS OF THE VERTEBRATE RETINA

1969 ◽  
pp. 223
Author(s):  
Richard W. Young
Keyword(s):  
Outer Segment ◽  
Photoreceptor Cells ◽  
Vertebrate Retina

scholarly journals Glycolytic reliance promotes anabolism in photoreceptors

2017 ◽  
Author(s):  
Yashodhan Chinchore ◽  
Tedi Begaj ◽  
David Wu ◽  
Eugene Drokhlyansky ◽  
Constance L. Cepko
Keyword(s):  
Outer Segment ◽  
Atp Hydrolysis ◽  
Carbon Allocation ◽  
Aerobic Glycolysis ◽  
Neuronal Cell ◽  
Photoreceptor Cells ◽  
Glycolytic Pathway ◽  
Membrane Excitability ◽  
Proliferating Cells ◽  
Genetic Perturbations

Sensory neurons capture information from the environment and convert it into signals that can greatly impact the survival of an organism. These systems are thus under heavy selective pressure, including for the most efficient use of energy to support their sensitivity and efficiency1. In this regard, the vertebrate photoreceptor cells face a dual challenge. They not only need to preserve their membrane excitability via ion pumps by ATP hydrolysis2 but also maintain a highly membrane rich organelle, the outer segment, which is the primary site of phototransduction, creating a considerable biosynthetic demand. How photoreceptors manage carbon allocation to balance their catabolic and anabolic demands is poorly understood. One metabolic feature of the retina is its ability to convert the majority of its glucose into lactate3,4 even in the presence of oxygen. This phenomenon, aerobic glycolysis, is found in cancer and proliferating cells, and is thought to promote biomass buildup to sustain proliferation5,6. The purpose of aerobic glycolysis in the retina, its relevance to photoreceptor physiology, and its regulation, are not understood. Here, we show that rod photoreceptors rely on glycolysis for their outer segment (OS) biogenesis. Genetic perturbations targeting allostery or key regulatory nodes in the glycolytic pathway impacted the OS size. Fibroblast growth factor (FGF) signaling was found to regulate glycolysis, with antagonism of this pathway resulting in anabolic deficits. These data demonstrate the cell autonomous role of the glycolytic pathway in OS maintenance and provide evidence that aerobic glycolysis is part of a metabolic program that supports the biosynthetic needs of a normal neuronal cell type.

scholarly journals Radioimmunocytochemical localization of retinal S-antigen with monoclonal antibodies.

1984 ◽  
Vol 32 (8) ◽  
pp. 834-838 ◽  
Author(s):  
N D Das ◽  
R J Ulshafer ◽  
Z S Zam ◽  
V R Leverenz ◽  
H Shichi
Keyword(s):  
Monoclonal Antibodies ◽  
Outer Segment ◽  
Antigenic Site ◽  
Photoreceptor Cells ◽  
Apical Region ◽  
Rod Photoreceptor ◽  
Inner Limiting Membrane ◽  
Silver Grains ◽  
Homogeneous Preparation ◽  
Labeling Pattern

Two monoclonal antibodies (RSA1/83 and RSA2/83) were developed against a homogeneous preparation of bovine retinal S-antigen. The two hybridomas produced by mouse X mouse hybrid myeloma cells secrete immunoglobulin G. Indirect autoradiography on glutaraldehyde-fixed preparations of bovine explants was used to locate the antigenic site. Antibody RSA1/83 recognizes the antigen primarily in the apical region of the rod outer segment, while antibody RSA2/83 located the antigen both in the outer and inner segments of the rod photoreceptor cells. A distinct band of silver grains also appeared along the inner limiting membrane with both antibodies. Control explants showed no specific labeling pattern over the various retinal compartments.

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 Phagocytosis of Retinal Rod and Cone Photoreceptors

Physiology ◽  
2010 ◽  
Vol 25 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Brian M. Kevany ◽  
Krzysztof Palczewski
Keyword(s):  
Outer Segment ◽  
Photoreceptor Cell ◽  
Current Knowledge ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Cells ◽  
Constant Length ◽  
Outer Segments ◽  
Retinal Rod ◽  
Rod And Cone Photoreceptors

Photoreceptor cells maintain a roughly constant length by continuously generating new outer segments from their base while simultaneously releasing mature outer segments engulfed by the retinal pigment epithelium (RPE). Thus postmitotic RPE cells phagocytose an immense amount of material over a lifetime, disposing of photoreceptor cell waste while retaining useful content. This review focuses on current knowledge of outer segment phagocytosis, discussing the steps involved along with their critical participants as well as how various perturbations in outer segment (OS) disposal can lead to retinopathies.

Subcellular localization of phosducin in rod photoreceptors

2005 ◽  
Vol 22 (1) ◽  
pp. 19-25 ◽  
Author(s):  
JING CHEN ◽  
TATSURO YOSHIDA ◽  
KOICHI NAKANO ◽  
MARK W. BITENSKY
Keyword(s):  
Subcellular Localization ◽  
Dark Adaptation ◽  
Outer Segment ◽  
Photoreceptor Cells ◽  
Immunogold Labeling ◽  
Synaptic Function ◽  
Immunogold Electron Microscopy ◽  
Rod Photoreceptors ◽  
Relative Paucity

Phosducin (Pd) is a 28-kD phosphoprotein whose expression in retina appears limited to photoreceptor cells. Pd binds to the β,γ subunits of transducin (Gt). Their binding affinity is markedly diminished by Pd phosphorylation. While Pd has long been regarded as a candidate for the regulation of Gt, the molecular details of Pd function remain unclear. This gap in understanding is due in part to a lack of precise information concerning the total amount and subcellular localization of rod Pd. While earlier studies suggested that Pd was a rod outer segment (ROS) protein, recent findings have demonstrated that Pd is distributed throughout the rod. In this report, the subcellular distribution and amounts of rat Pd are quantified with immunogold electron microscopy. After light or dark adaptation, retinal tissues were fixedin situand prepared for ultrathin sectioning and immunogold labeling. Pd concentrations were analyzed over the entire length of the rod. The highest Pd labeling densities were found in the rod synapse. Less intense Pd staining was observed in the ellipsoid and myoid regions, while minimal labeling densities were found in the ROS and the rod nucleus. In contrast with rod Gt, no evidence was found for light-dependent movement of Pd between inner and outer segments. There is a relative paucity of Pd in the ROS as compared with the large amounts of Gtfound there. This does not support the earlier idea that Pd could modulate Gtactivity by controlling its concentration. On the other hand, the presence of Pd in the nucleus is consistent with its possible role as a regulator of transcription. The functions of Pd in the ellipsoid and myoid regions remain unclear. The highest concentration of Pd was found at the rod synapse, consistent with a suggested role for Pd in the regulation of synaptic function.

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.

scholarly journals Dysfunction of Heterotrimeric Kinesin-2 in Rod Photoreceptor Cells and the Role of Opsin Mislocalization in Rapid Cell Death

2010 ◽  
Vol 21 (23) ◽  
pp. 4076-4088 ◽  
Author(s):  
Vanda S. Lopes ◽  
David Jimeno ◽  
Kornnika Khanobdee ◽  
Xiaodan Song ◽  
Bryan Chen ◽  
...  
Keyword(s):  
Cell Death ◽  
Outer Segment ◽  
Photoreceptor Cell ◽  
Photoreceptor Cells ◽  
Cell Loss ◽  
Rod Photoreceptor ◽  
Retinal Degenerations ◽  
Cell Counts ◽  
And Function

Due to extensive elaboration of the photoreceptor cilium to form the outer segment, axonemal transport (IFT) in photoreceptors is extraordinarily busy, and retinal degeneration is a component of many ciliopathies. Functional loss of heterotrimeric kinesin-2, a major anterograde IFT motor, causes mislocalized opsin, followed by rapid cell death. Here, we have analyzed the nature of protein mislocalization and the requirements for the death of kinesin-2-mutant rod photoreceptors. Quantitative immuno EM showed that opsin accumulates initially within the inner segment, and then in the plasma membrane. The light-activated movement of arrestin to the outer segment is also impaired, but this defect likely results secondarily from binding to mislocalized opsin. Unlike some other retinal degenerations, neither opsin–arrestin complexes nor photoactivation were necessary for cell loss. In contrast, reduced rod opsin expression provided enhanced rod and cone photoreceptor survival and function, as measured by photoreceptor cell counts, apoptosis assays, and ERG analysis. The cell death incurred by loss of kinesin-2 function was almost completely negated by Rho−/−. Our results indicate that mislocalization of opsin is a major cause of photoreceptor cell death from kinesin-2 dysfunction and demonstrate the importance of accumulating mislocalized protein per se, rather than specific signaling properties of opsin, stemming from photoactivation or arrestin binding.

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