This gene encodes an enzyme that plays a role in the recovery of retinal photoreceptors from photobleaching. This enzyme promotes the activity of retinal guanylyl cyclase-1 (GC1) at low calcium concentrations and inhibits GC1 at high calcium concentrations. Mutations in this gene can cause cone dystrophy 3 and code-rod dystrophy 14. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2016],
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Function:
Disease:Defects in GUCA1A are the cause of cone dystrophy type 3 (COD3) [MIM:602093]. COD3 is an autosomal dominant cone dystrophy. Cone dystrophies are retinal dystrophies characterized by progressive degeneration of the cone photoreceptors with preservation of rod function, as indicated by electroretinogram. However, some rod involvement may be present in some cone dystrophies, particularly at late stage. Affected individuals suffer from photophobia, loss of visual acuity, color vision and central visual field. Another sign is the absence of macular lesions for many years. Cone dystrophies are distinguished from the cone-rod dystrophies, in which some loss of peripheral vision also occurs.,Function:Stimulates guanylyl cyclase 1 (GC1) when free calcium ions concentration is low and inhibits GC1 when free calcium ions concentration is elevated. This Ca(2+)-sensitive regulation of GC is a key event in recovery of the dark state of rod photoreceptors following light exposure.,miscellaneous:Binds three calcium ions.,online information:Retina International's Scientific Newsletter,similarity:Contains 4 EF-hand domains.,tissue specificity:Retina; cone outer and inner segments, in particular, in disk membrane regions, and to a lesser extent rod inner and outer segments.,
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Cellular Localization:
Membrane; Lipid-anchor . Photoreceptor inner segment . Cell projection, cilium, photoreceptor outer segment . Present at higher levels in cone than in rod outer segments (PubMed:9620085). Subcellular location is not affected by light or dark conditions. .
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Tissue Expression:
In the retina, it is expressed in rod and cone photoreceptors.