Cone dystrophy

Figure 5. Cartoon of the human GC1 gene and GC1 disease mutations. In general, null mutations are associated with recessive LCA, whereas missense mutations in the dimerization domain are associated with dominant cone dystrophy...

GCAP1(L151F) mutations affecting the EF4-hand motif linked to dominant cone dystrophy and cone-rod dystrophy were identified in two unrelated families. In one family (Sokal et al., 2004), affected family members experienced dyschro-matopsia, hemeralopia, and reduced visual acuity by the second to third decade... 

THE BIOCHEMICAL PHENOTYPE OF CONE DYSTROPHIES ASSOCIATED WITH EF-HAND MOTIF MUTATIONS... 

Stephen, R., Palczewski, K., and Sousa, M.C. (2006). The crystal structure ofGCAP3 suggests molecular mechanism of GCAP-linked cone dystrophies. J. Mol. Biol. 359 266-275. 

Jacobson DM, Thompson HS, Bartley JA (1989) X-linked progressive cone dystrophy. Clinical characteristics of affected males and female carriers. Ophthalmology 96 885-895. 

Calbindin D-28K is an example of a calcium-binding protein of the EF hand family that is not enriched through its calcium-dependent binding to phenyl-Sepharose. Instead, it can be readily purified by binding to DEAE-Sepharose in low calcium and eluted by increased calcium (Figure 2, lane h). Our studies demonstrate that calbindin D-28K is expressed in peripheral and perifoveal cone cells of the human retina but not in parafoveal or foveal cones, and this pattern of expression parallels the degeneration of photoreceptor cells seen in some humans with rod-cone dystrophies. 

The ribbon is composed mainly of the structural protein, Ribeye, but also includes a kinesin motor protein, KIF3A, and Rab3-interacting protein, RIM. Ribbons are attached to the synaptic active zone by bassoon, and its structural relative, piccolo. Although the ribbon appears to anchor a readily releasable pool of vesicles, molecular motors do not appear to be involved in vesicle movements near the active zone. RDVt protein mutations have been implicated in an autosomal dominant rod-cone dystrophy (Johnson et al., 2003). 

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