Linked Life Data

15240799

Source:http://linkedlifedata.com/resource/pubmed/id/15240799

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
27
pubmed:dateCreated
2004-7-8
pubmed:abstractText
Guanylyl cyclase-activating proteins (GCAPs) are Ca2+-binding proteins that activate guanylyl cyclase when free Ca2+ concentrations in retinal rods and cones fall after illumination and inhibit the cyclase when free Ca2+ reaches its resting level in the dark. Several forms of retinal dystrophy are caused by mutations in GUCA1A, the gene coding for GCAP1. To investigate the cellular mechanisms affected by the diseased state, we created transgenic mice that express GCAP1 with a Tyr99Cys substitution (Y99C GCAP1) found in human patients with a late-onset retinal dystrophy (Payne et al., 1998). Y99C GCAP1 shifted the Ca2+ sensitivity of the guanylyl cyclase in photoreceptors, keeping it partially active at 250 nM free Ca2+, the normal resting Ca2+ concentration in darkness. The enhanced activity of the cyclase in the dark increased cyclic nucleotide-gated channel activity and elevated the rod outer segment Ca2+ concentration in darkness, measured by using fluo-5F and laser spot microscopy. In different lines of transgenic mice the magnitude of this effect rose with the Y99C GCAP1 expression. Surprisingly, there was little change in the rod photoresponse, indicating that dynamic Ca2+-dependent regulation of cGMP synthesis was preserved. However, the photoreceptors in these mice degenerated, and the rate of the cell loss increased with the level of the transgene expression, unlike in transgenic mice that overexpressed normal GCAP1. These results provide the first direct evidence that a mutation linked to congenital blindness increases Ca2+ in the outer segment, which may trigger the apoptotic process.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1529-2401
pubmed:author
pubmed:issnType
Electronic
pubmed:day
7
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6078-85
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:15240799-Amino Acid Substitution, pubmed-meshheading:15240799-Animals, pubmed-meshheading:15240799-Apoptosis, pubmed-meshheading:15240799-Calcium, pubmed-meshheading:15240799-Calcium-Binding Proteins, pubmed-meshheading:15240799-Cattle, pubmed-meshheading:15240799-Cell Separation, pubmed-meshheading:15240799-Dark Adaptation, pubmed-meshheading:15240799-Electrophysiology, pubmed-meshheading:15240799-Electroretinography, pubmed-meshheading:15240799-Guanylate Cyclase, pubmed-meshheading:15240799-Guanylate Cyclase-Activating Proteins, pubmed-meshheading:15240799-Intracellular Fluid, pubmed-meshheading:15240799-Mice, pubmed-meshheading:15240799-Mice, Inbred C57BL, pubmed-meshheading:15240799-Mice, Transgenic, pubmed-meshheading:15240799-Mutation, Missense, pubmed-meshheading:15240799-Photic Stimulation, pubmed-meshheading:15240799-Photoreceptor Cells, Vertebrate, pubmed-meshheading:15240799-Receptors, Cell Surface, pubmed-meshheading:15240799-Retina, pubmed-meshheading:15240799-Retinal Degeneration
pubmed:year
2004
pubmed:articleTitle
The Y99C mutation in guanylyl cyclase-activating protein 1 increases intracellular Ca2+ and causes photoreceptor degeneration in transgenic mice.
pubmed:affiliation
Hafter Research Laboratories, Pennsylvania College of Optometry, Elkins Park, Pennsylvania 19027, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.