scholarly journals Deletion of the p85α Regulatory Subunit of Phosphoinositide 3-Kinase in Cone Photoreceptor Cells Results in Cone Photoreceptor Degeneration

2011 ◽  
Vol 52 (6) ◽  
pp. 3775 ◽  
Author(s):  
Ivana Ivanovic ◽  
Robert E. Anderson ◽  
Yun Z. Le ◽  
Steven J. Fliesler ◽  
David M. Sherry ◽  
...  
Keyword(s):  
Photoreceptor Cells ◽  
Regulatory Subunit ◽  
Cone Photoreceptor ◽  
Photoreceptor Degeneration ◽  
Phosphoinositide 3 Kinase

scholarly journals Loss of Class III Phosphoinositide 3-Kinase Vps34 Results in Cone Degeneration

Biology ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 384
Author(s):  
Ammaji Rajala ◽  
Feng He ◽  
Robert E. Anderson ◽  
Theodore G. Wensel ◽  
Raju V. S. Rajala
Keyword(s):  
Gene Knockout ◽  
Substantial Reduction ◽  
Photoreceptor Cells ◽  
Mouse Retina ◽  
Cone Photoreceptor ◽  
Class Iii ◽  
Cone Function ◽  
Rod Function ◽  
Phosphoinositide 3 Kinase ◽  
Phosphatidylinositol 3

The major pathway for the production of the low-abundance membrane lipid phosphatidylinositol 3-phosphate (PI(3)P) synthesis is catalyzed by class III phosphoinositide 3-kinase (PI3K) Vps34. The absence of Vps34 was previously found to disrupt autophagy and other membrane-trafficking pathways in some sensory neurons, but the roles of phosphatidylinositol 3-phosphate and Vps34 in cone photoreceptor cells have not previously been explored. We found that the deletion of Vps34 in neighboring rods in mouse retina did not disrupt cone function up to 8 weeks after birth, despite diminished rod function. Immunoblotting and lipid analysis of cones isolated from the cone-dominant retinas of the neural retina leucine zipper gene knockout mice revealed that both PI(3)P and Vps34 protein are present in mouse cones. To determine whether Vps34 and PI(3)P are important for cone function, we conditionally deleted Vps34 in cone photoreceptor cells of the mouse retina. Overall retinal morphology and rod function appeared to be unaffected. However, the loss of Vps34 in cones resulted in the loss of structure and function. There was a substantial reduction throughout the retina in the number of cones staining for M-opsin, S-opsin, cone arrestin, and peanut agglutinin, revealing degeneration of cones. These studies indicate that class III PI3K, and presumably PI(3)P, play essential roles in cone photoreceptor cell function and survival.

scholarly journals The cGMP-Dependent Protein Kinase 2 Contributes to Cone Photoreceptor Degeneration in the Cnga3-Deficient Mouse Model of Achromatopsia

2020 ◽  
Vol 22 (1) ◽  
pp. 52
Author(s):  
Mirja Koch ◽  
Constanze Scheel ◽  
Hongwei Ma ◽  
Fan Yang ◽  
Michael Stadlmeier ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mouse Model ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Cone Photoreceptor ◽  
Photoreceptor Degeneration ◽  
Dependent Protein Kinase ◽  
Genetic Ablation ◽  
Cgmp Dependent Protein Kinase ◽  
Dependent Protein

Mutations in the CNGA3 gene, which encodes the A subunit of the cyclic guanosine monophosphate (cGMP)-gated cation channel in cone photoreceptor outer segments, cause total colour blindness, also referred to as achromatopsia. Cones lacking this channel protein are non-functional, accumulate high levels of the second messenger cGMP and degenerate over time after induction of ER stress. The cell death mechanisms that lead to loss of affected cones are only partially understood. Here, we explored the disease mechanisms in the Cnga3 knockout (KO) mouse model of achromatopsia. We found that another important effector of cGMP, the cGMP-dependent protein kinase 2 (Prkg2) is crucially involved in cGMP cytotoxicity of cones in Cnga3 KO mice. Virus-mediated knockdown or genetic ablation of Prkg2 in Cnga3 KO mice counteracted degeneration and preserved the number of cones. Analysis of markers of endoplasmic reticulum stress and unfolded protein response confirmed that induction of these processes in Cnga3 KO cones also depends on Prkg2. In conclusion, we identified Prkg2 as a novel key mediator of cone photoreceptor degeneration in achromatopsia. Our data suggest that this cGMP mediator could be a novel pharmacological target for future neuroprotective therapies.

scholarly journals Fission Yeast Rad26 Is a Regulatory Subunit of the Rad3 Checkpoint Kinase

2002 ◽  
Vol 13 (2) ◽  
pp. 480-492 ◽  
Author(s):  
Tom D. Wolkow ◽  
Tamar Enoch
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Fission Yeast ◽  
Complex Analysis ◽  
Kinase Activity ◽  
Regulatory Subunit ◽  
Kinase Activation ◽  
Checkpoint Proteins ◽  
Cycle Arrest ◽  
Phosphoinositide 3 Kinase

Fission yeast Rad3 is a member of a family of phosphoinositide 3-kinase -related kinases required for the maintenance of genomic stability in all eukaryotic cells. In fission yeast, Rad3 regulates the cell cycle arrest and recovery activities associated with the G2/M checkpoint. We have developed an assay that directly measures Rad3 kinase activity in cells expressing physiological levels of the protein. Using the assay, we demonstrate directly that Rad3 kinase activity is stimulated by checkpoint signals. Of the five other G2/M checkpoint proteins (Hus1, Rad1, Rad9, Rad17, and Rad26), only Rad26 was required for Rad3 kinase activity. Because Rad26 has previously been shown to interact constitutively with Rad3, our results demonstrate that Rad26 is a regulatory subunit, and Rad3 is the catalytic subunit, of the Rad3/Rad26 kinase complex. Analysis of Rad26/Rad3 kinase activation in rad26.T12, a mutant that is proficient for cell cycle arrest, but defective in recovery, suggests that these two responses to checkpoint signals require quantitatively different levels of kinase activity from the Rad3/Rad26 complex.

scholarly journals Disease sequence from mutant rhodopsin allele to rod and cone photoreceptor degeneration in man

1998 ◽  
Vol 95 (12) ◽  
pp. 7103-7108 ◽  
Author(s):  
A. V. Cideciyan ◽  
D. C. Hood ◽  
Y. Huang ◽  
E. Banin ◽  
Z.-Y. Li ◽  
...  
Keyword(s):  
Cone Photoreceptor ◽  
Photoreceptor Degeneration

scholarly journals KIT ligand protects against both light-induced and genetic photoreceptor degeneration

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Huirong Li ◽  
Lili Lian ◽  
Bo Liu ◽  
Yu Chen ◽  
Jinglei Yang ◽  
...  
Keyword(s):  
Photoreceptor Cells ◽  
Nuclear Accumulation ◽  
Tyrosine Kinase Receptor ◽  
Light Damage ◽  
Photoreceptor Degeneration ◽  
Kit Mutation ◽  
Kit Ligand ◽  
Retinal Degenerative Diseases ◽  
Experimental Expression ◽  
Inherited Retinal Degeneration

Photoreceptor degeneration is a major cause of blindness and a considerable health burden during aging but effective therapeutic or preventive strategies have not so far become readily available. Here, we show in mouse models that signaling through the tyrosine kinase receptor KIT protects photoreceptor cells against both light-induced and inherited retinal degeneration. Upon light damage, photoreceptor cells upregulate Kit ligand (KITL) and activate KIT signaling, which in turn induces nuclear accumulation of the transcription factor NRF2 and stimulates the expression of the antioxidant gene Hmox1. Conversely, a viable Kit mutation promotes light-induced photoreceptor damage, which is reversed by experimental expression of Hmox1. Furthermore, overexpression of KITL from a viral AAV8 vector prevents photoreceptor cell death and partially restores retinal function after light damage or in genetic models of human retinitis pigmentosa. Hence, application of KITL may provide a novel therapeutic avenue for prevention or treatment of retinal degenerative diseases.

Initiation and maintenance of NGF-stimulated neurite outgrowth requires activation of a phosphoinositide 3-kinase

1996 ◽  
Vol 109 (2) ◽  
pp. 289-300 ◽  
Author(s):  
T.R. Jackson ◽  
I.J. Blader ◽  
L.P. Hammonds-Odie ◽  
C.R. Burga ◽  
F. Cooke ◽  
...  
Keyword(s):  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Specific Inhibitor ◽  
Morphological Differentiation ◽  
Sympathetic Neuron ◽  
Neuronal Morphology ◽  
Regulatory Subunit ◽  
Membrane Reorganization ◽  
Phosphoinositide 3 Kinase

Application of nerve growth factor (NGF) to PC12 cells stimulates a programme of physiological changes leading to the development of a sympathetic neuron like phenotype, one aspect of which is the development of a neuronal morphology characterised by the outgrowth of neuritic processes. We have investigated the role of phosphoinositide 3-kinase in NGF-stimulated morphological differentiation through two approaches: firstly, preincubation with wortmannin, a reputedly specific inhibitor of phosphoinositide kinases, completely inhibited initial morphological responses to NGF, the formation of actin filament rich microspikes and subsequent neurite outgrowth. This correlated with wortmannin inhibition of NGF-stimulated phosphatidylinositol(3,4,5)trisphosphate (PtdInsP3) and phosphatidylinositol(3,4)bisphosphate (PtdIns(3,4)P2) production and with inhibition of NGF-stimulated phosphoinositide 3-kinase activity in anti-phosphotyrosine immunoprecipitates. Secondly, the overexpression of a mutant p85 regulatory subunit of the phosphoinositide 3-kinase, which cannot interact with the catalytic p110 subunit, also substantially inhibited the initiation of NGF-stimulated neurite outgrowth. In addition, we found that wortmannin caused a rapid collapse of more mature neurites formed following several days exposure of PC12 cells to NGF. These results indicate that NGF-stimulated neurite outgrowth requires the activity of a tyrosine kinase regulated PI3-kinase and suggest that the primary product of this enzyme, PtdInsP3, is a necessary second messenger for the cytoskeletal and membrane reorganization events which occur during neuronal differentiation.

scholarly journals Upregulated gga-miR-16-5p Inhibits the Proliferation Cycle and Promotes the Apoptosis of MG-Infected DF-1 Cells by Repressing PIK3R1-Mediated the PI3K/Akt/NF-κB Pathway to Exert Anti-Inflammatory Effect

2019 ◽  
Vol 20 (5) ◽  
pp. 1036 ◽  
Author(s):  
Kang Zhang ◽  
Yun Han ◽  
Yabo Zhao ◽  
Yingfei Sun ◽  
Mengyun Zou ◽  
...  
Keyword(s):  
Opposite Effect ◽  
Chronic Respiratory Disease ◽  
Regulatory Subunit ◽  
Cell Multiplication ◽  
Necrosis Factor Alpha ◽  
Cycle Progression ◽  
Multiplication Cycle ◽  
Anti Inflammatory ◽  
Phosphoinositide 3 Kinase ◽  
Inflammatory Effect

Mycoplasma gallisepticum (MG) mainly infects chickens to initiate chronic respiratory disease (CRD). microRNAs (miRNAs) play vital roles according to previously reported studies. Our previous study showed that gga-miR-16-5p, in MG-infected lungs of chicken embryo, was upregulated by Illumina sequencing. The study aimed to reveal what role gga-miR-16-5p plays in CRD progression. gga-miR-16-5p was upregulated in MG-infected fibroblast cells (DF-1). Phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) was demonstrated as the target gene of gga-miR-16-5p. Furthermore, PIK3R1 expression was lower in MG-infected groups than it in noninfected controls measured by qPCR. Additionally, overexpressed gga-miR-16-5p could downregulate PIK3R1 and phosphorylated serine/threonine kinase (p-Akt) to express protein, whereas there is an opposite effect on inhibition. Overexpressed gga-miR-16-5p resulted in decreased activity of tumor necrosis factor alpha (TNF-α) and the nuclear factor-kappaB (NF-κB) by qPCR. Furthermore, overexpressed gga-miR-16-5p restricted cell multiplication, cycle progression, and increased apoptosis of MG-infected DF-1 cells, whereas inhibited gga-miR-16-5p led to the opposite effect. Collectively, upregulated gga-miR-16-5p could decrease multiplication, cycle progression, and increase apoptosis of MG-infected DF-1 cells, at least partly through directly targeting PIK3R1 and inhibiting PI3K/Akt/NF-κB pathway to exert an anti-inflammatory effect. Our results will provide more experimental evidence to bring pathogenesis of MG infection to light.

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