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At least 127 records · Page 7Linked to original sources
PubMed2002

Antirecoverin antibody in the aqueous humor of a patient with cancer-associated retinopathy.

PURPOSE: To describe a patient with cancer-associated retinopathy (CAR) in whom antirecoverin antibody was found in the aqueous humor. DESIGN: Interventional case report. METHODS: A 65-year-old man underwent resection of adenocarcinoma of the lung in June 1991 and noted deterioration of vision 10 months later. Goldmann perimetry revealed a ring-like scotoma in each eye, and the electroretinogram was nonrecordable. Aqueous humor and peripheral venous blood were collected for Western blot analysis from this patient and three other patients during surgery for age-related cataract. RESULTS: We found antirecoverin antibody within the aqueous humor and serum in the patient with CAR. In contrast, such imunoreactivities were not observed in specimens from the control patients. CONCLUSION: These observations strongly suggest that antirecoverin antibody penetrates into the aqueous humor and vitreous cavity beyond the blood-retina barrier in CAR.

Adenocarcinoma↗
PubMed1996

Cancer-associated retinopathy in a patient with endometrial cancer.

PURPOSE: We studied a case of unusual retinopathy in a 60-year-old woman. METHOD: The patient developed bilateral retinopathy with iridocyclitis and vitreitis. Corticosteroid therapy could not prevent deterioration of visual acuity and field. The electroretinogram became nonrecordable, and fluorescein angiogram exhibited retinal pigment epithelium window defects, fluorescein stainings to the vascular walls, and narrowed arterioles. RESULTS: The patient underwent hysterectomy and lymphadenectomy for endometrial cancer in the corporis uteri. She was found to possess antibodies against retinal 34-kd protein, leading to a diagnosis of cancer-associated retinopathy. CONCLUSION: Cancer-associated retinopathy may occur in patients with endometrial cancer of the corporis uteri.

Antibodies, Neoplasm↗
PubMed1996

Mapping of autosomal dominant cone degeneration to chromosome 17p.

PURPOSE: We studied a single, large family with autosomal dominant cone degeneration in order to map the disease-causing gene. METHODS: Seventy-three individuals in this family were examined, and 34 were found to be affected. Blood samples from 34 affected and unaffected family members were obtained for DNA analysis and linkage mapping. Fifty-three genetic markers were analyzed in this family by using short tandem repeat markers. These markers were primarily in candidate genomic regions. RESULTS: Marker D17S796 generated a significantly positive LOD score of 4.21 (theta = .04; 10,000:1 odds in favor of linkage). Marker D17S513 gave a significant LOD score of 3.1 (theta = .096; 1,000:1 odds in favor of linkage). Other markers in the region generated suggestive findings, such as D17S786, with a LOD score of 2.7, and D17S945, with a LOD score of 2.41. CONCLUSIONS: Our results indicate that a genetic defect that causes autosomal dominant cone degeneration is located on chromosome 17p in the region of recoverin. Recoverin, a retinal expressed gene, is an appealing candidate for this disease.

Adolescent↗
PubMed1997

Autoimmune retinopathy in the absence of cancer.

PURPOSE: To report the clinical and immunologic features of two patients with progressive retinal degeneration and circulating antiretinal antibodies without systemic malignancy. METHODS: Two patients were followed up for 5 to 7 years. Comprehensive medical and ophthalmic examinations and visual function testing included manual perimetry and standardized electroretinography. Patient sera were tested for antiretinal antibodies by Western blot and immunoperoxidase indirect cytochemistry techniques. RESULTS: Two patients had family history of autoimmune disease. Each had severe monocular visual loss with photopsia, a ring scotoma, and abnormal electroretinogram despite a normal-appearing ocular fundus. One had a flat electroretinogram; the other had inner retina dysfunction, with selective b wave loss and abnormal oscillatory potentials. Both patients' sera had antiretinal antibodies that specifically labeled the inner plexiform layer of donor retina by indirect immunoperoxidase testing. Neither had any sign of cancer. CONCLUSIONS: In two patients without systemic malignancy, the symptoms, perimetric findings, and normal fundus appearance resembled cancer associated retinopathy. Electroretinography and antibody findings indicating dysfunction of the inner retina are distinct from those of cancer-associated retinopathy. These two cases raise the possibility of an autoimmune mechanism for retinal degeneration that is not cancer associated. Further study is necessary to determine the role of antiretinal antibodies in these patients.

Adult↗
PubMed1996

Cancer-associated retinopathy with presumed vasculitis.

PURPOSE: To treat a 63-year-old woman who experienced fairly rapid vision loss in association with small-cell carcinoma of the lung. METHODS: She underwent a full ophthalmologic examination, including fluorescein angiography and an immunologic study by Western blot analysis. RESULTS: Fluorescein angiography demonstrated diffuse staining of the retinal vessels. She had 62-kd antiretinal antibody in her serum. Cancer-associated retinopathy was diagnosed. CONCLUSION: The staining seen on the angiogram appears to indicate vasculitis, which would cause the characteristic attenuation of retinal vessels in this disease.

Anti-Inflammatory Agents↗
PubMed1998

Recoverin-associated retinopathy: a clinically and immunologically distinctive disease.

PURPOSE: To compare the immune response to retinal antigens in a patient with a clinical condition resembling cancer-associated retinopathy with the immune responses of patients with other retinal degenerations or uveitis. METHODS: Cellular and humoral immune responses to retinal S-antigen and recoverin were determined in one patient with disease resembling cancer-associated retinopathy, three patients with other retinal degenerations, and eight patients with uveitis. RESULTS: A cellular immune response against recoverin was found only in the patient with the condition resembling cancer-associated retinopathy. Elevated levels of antibody against recoverin were found in this patient and in one of the three patients with a retinal degeneration, but in none of the eight patients with uveitis. In contrast, moderate lymphocyte responses to retinal S-antigen were found in most of the patients studied, and this response did not distinguish among the patient groups. Levels of serum antibodies against retinal S-antigen were also similar in all patients tested. Serum from the patient with disease resembling cancer-associated retinopathy produced strong immunostaining of the rods, cones, outer plexiform layer, and some cone bipolar cells, but serum from the patients with uveitis or other retinal degenerations did not show specific reactivity with the retina. CONCLUSIONS: We propose that this immunologically and clinically distinctive condition be termed recoverin-associated retinopathy, and we suggest that a cellular immune response against recoverin may be a distinguishing feature of the disorder.

Adenolymphoma↗
PubMed2003

Aberrantly expressed recoverin is functionally associated with G-protein-coupled receptor kinases in cancer cell lines.

Cancer-associated retinopathy (CAR) is an ocular manifestation of a paraneoplastic syndrome whereby immunological reactions toward recoverin (Rec), a retina-specific Ca(2+) binding protein, and its aberrant expression in tumor cells lead to the retinal degeneration. To elucidate functional roles of the aberrantly expression in cancer cells, we performed immunoprecipitation using anti-human Rec mAb. We observed co-precipitation of G-protein-coupled receptor kinases (GRKs) and caveolin-1 with Rec from cell lysates of 293 or SSTW cells. Immunocytochemistry revealed that immunoreactivities toward Rec within the cancer cells were almost identical to those toward GRKs and caveolin-1. The present data strongly suggest that aberrantly expressed Rec should be involved in the GRK-dependent cellular regulation in cancer cells.

Antibodies, Monoclonal↗
PubMed1992

cDNA cloning of a neural visinin-like Ca(2+)-binding protein.

A 21,000-dalton Ca(2+)-binding protein (Walsh, M.P., Valentine, K.A., Ngai, P.K., Carruthers, C.A., and Hollengerg, M.D. (1984) Biochem. J. 224, 117-127) was purified from the rat brain and through the use of oligonucleotide probe based on partial amino acid sequence, cDNA clones were obtained from rat brain cDNA library. The complete amino acid sequence deduced from the cDNA contains 191 residues and has a calculated molecular mass of 22,142 daltons. There are three potential Ca(2+)-binding sites like the EF hands in the sequence. It displays striking sequence homology with visinin and recoverin, retina-specific Ca(2+)-binding proteins. Northern blot analysis revealed that the protein is highly and specifically expressed in the brain.

Amino Acid Sequence↗
PubMed1992

Purification and characterization of S-modulin, a calcium-dependent regulator on cGMP phosphodiesterase in frog rod photoreceptors.

S-modulin is a 26 kDa protein that regulates light sensitivity of cGMP phosphodiesterase in a Ca(2+)-dependent manner in frog rod outer segments (ROSs). In the present study, we purified S-modulin by taking advantage of a hydrophobic interaction between Phenyl Sepharose and S-modulin at high Ca2+ concentrations. The yield was greater than 90%. 45Ca(2+)-binding experiment showed that S-modulin is a Ca(2+)-binding protein. At high Ca2+ concentrations, S-modulin binds to ROS membranes. The binding target of the Ca2+/S-modulin complex is possibly a ROS membrane lipid(s), but it was difficult to identify. The binding was observed mainly at greater than 1 microM Ca2+. The amino acid sequence deduced from proteolytic fragments of S-modulin was approximately 80% and 60% identical to those of recovering and visinin, respectively.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1992

Isolation of human retinal genes: recoverin cDNA and gene.

A human retina cDNA library enriched for retina-specific clones was prepared by subtraction with a non-retina population of cDNA in combination with polymerase chain reaction (PCR) amplifications. A highly retina-specific cDNA clone (1190 bp) was obtained through this library encoding a 200 amino acid protein with three calcium binding sites and 87% homology to the bovine photoreceptor protein, recoverin, which has been shown to mediate the recovery of the dark current after photoactivation, and 58% homology to the calcium-binding chick cone protein, visinin. Analysis of the gene indicated a 9-10 kb single-copy gene with at least three exons and two introns. The three exons contained the entire coding sequence, and all of the calcium-binding EF-hand regions were in putative exon 1. The recoverin gene was mapped to human chromosome 17 by hybridization to a panel of human-rodent hybrid DNAs.

Amino Acid Sequence↗
PubMed2002

Measurement of membrane binding between recoverin, a calcium-myristoyl switch protein, and lipid bilayers by AFM-based force spectroscopy.

Myristoyl switch is a feature of several peripheral membrane proteins involved in signal transduction pathways. This unique molecular property is best illustrated by the "Ca(2+)-myristoyl switch" of recoverin, which is a Ca(2+)-binding protein present in retinal rod cells of vertebrates. In this transduction pathway, the Ca(2+)-myristoyl switch acts as a calcium sensor involved in cell recovery from photoactivation. Ca(2+) binding by recoverin induces the extrusion of its myristoyl group to the solvent, which leads to its translocation from cytosol to rod disk membranes. Force spectroscopy, based on atomic force microscope (AFM) technology, was used to determine the extent of membrane binding of recoverin in the absence and presence of calcium, and to quantify this force of binding. An adhesion force of 48 +/- 5 pN was measured between recoverin and supported phospholipid bilayers in the presence of Ca(2+). However, no binding was observed in the absence of Ca(2+). Experiments with nonmyristoylated recoverin confirmed these observations. Our results are consistent with previously measured extraction forces of lipids from membranes.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1997

Rhodopsin phosphorylation in bovine rod outer segments is more sensitive to the inhibitory action of recoverin at the low rhodopsin bleaching than it is at the high bleaching.

Recoverin, a calcium-binding protein, is supposed to have rhodopsin kinase as a target in the retinal rod cell. In the present work, we show that efficiency of recoverin as an inhibitor of rhodopsin phosphorylation in bovine rod outer segments is inversely proportional to the level of rhodopsin bleaching. These results, together with the data obtained previously in a reconstituted system (Senin et al. (1997) Biochem. J. 321, 551-555), allow us to hypothesize that recoverin might be responsible for a Ca2(+)-dependent regulation of the kinase in vivo, preventing it from participating in the phosphorylation of unbleached rhodopsin.

Adenosine Triphosphate↗
PubMed1998

Obtaining and characterization of EF-hand mutants of recoverin.

Several EF-hand recoverin mutants were obtained and their abilities to bind to photoreceptor membranes and to inhibit rhodopsin kinase were determined. The mutants with the 'spoiled' 2nd, 3rd or (2nd+3rd) EF-hand structures did not act upon the kinase activity in the microM range of Ca2+ concentrations. Mutations of the 4th EF hand, which 'repaired' its Ca2+-binding activity, resulted in recoverin with three 'working' Ca2+-binding sites. The latter mutant inhibited rhodopsin kinase even more effectively than the wild-type recoverin, containing two working Ca2+-binding structures.

Animals↗
PubMed2003

Functional restoration of the Ca2+-myristoyl switch in a recoverin mutant.

Recoverin is a neuronal calcium sensor protein that plays a crucial role in vertebrate phototransduction. It undergoes a Ca(2+)-myristoyl switch when Ca(2+) binds to its two functional EF-hand motifs (EF-hands 2 and 3), each present in one of recoverin's two domains. Impairment of Ca(2+)-binding in recoverin leads to a disturbance of the Ca(2+)-myristoyl switch and loss of its regulatory properties, i.e. inhibiton of rhodopsin kinase. We have engineered recoverin mutants with either of the two functional EF-hands disabled, but with a functional Ca(2+)-binding site in EF-hand 4. While a defect in EF-hand 2 could not be rescued by the additional EF-hand 4, the impairment of EF-hand 3 was powerfully compensated by Ca(2+)-binding to EF-hand 4. For example, the myristoylated form of the latter mutant bound to membranes in a Ca(2+)-dependent way and was able to inhibit rhodopsin kinase in a way similar to that of the wild-type protein. Thus, for recoverin to undergo a Ca(2+)-myristoyl switch, it is necessary and sufficient to have either of the two EF-hands in the second domain in a functional state. On the basis of these results and inspection of published three-dimensional structures of recoverin, we propose a model highlighting the mutual interdependence of sterical configurations in EF-hands 3 and 4 of recoverin.

Animals↗
PubMed2003

Invasive thymoma with paraneoplastic retinopathy.

A 60-year-old man was admitted for progressive visual loss in both eyes. He was diagnosed with retinopathy and chest computed tomography revealed an invasive thymoma. In western blot analysis, serum autoantibodies against recoverin, photoreceptor-specific calcium-binding protein, and heat shock cognate protein 70 which were identified as the cause of cancer-associated retinopathy (CAR). Immunofluorescence staining showed that thymoma cells also expressed recoverin. These observations strongly suggested that similar pathogenesis of CAR was involved in the presented case.

Biomarkers, Tumor↗