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Guanylyl cyclase activating protein (GCAP1) has been proposed to act as a calcium-dependent regulator of retinal photoreceptor guanylyl cyclase (GC) activity. Using immunocytochemical and biochemical methods, we show here that GCAP1 is present in rod and cone photoreceptor outer segments where phototransduction occurs. Recombinant and native GCAP1 activate(More)
Calbindin D-28K is a calcium-binding protein found in the cone but not rod photoreceptor cells in the retinas of a variety of species. Recent studies of the monkey retina indicated that calbindin D-28K may be expressed preferentially in non-foveal regions of the retina. In the current studies of human retinas, immunohistochemical experiments demonstrated(More)
PURPOSE Neuroblastoma is an aggressive childhood disease of the sympathetic nervous system. Treatments are often ineffective and have serious side effects. Because resveratrol, a natural plant product, has been reported to have limited toxicity at chemotherapeutic levels, we investigated its efficacy in the treatment of neuroblastoma as well as its(More)
Two minor proteins of frog rod outer segments become phosphorylated when retinas are incubated in the dark with 32Pi. The proteins, designated component I (13,000 daltons) and component II (12,000 daltons), are dephosphorylated when retinas are illuminated. The dephosphorylation is reversible; the two proteins are rephosphorylated when illumination ceases.(More)
In the presence of 10(-9) M calcium, rod outer segments freshly detached from dark-adapted frog retinas contain between 0.01 and 0.02 moles of guanosine 3',5'-cyclic monophosphate (cyclic GMP) per mole of rhodopsin. The dark level of cyclic GMP is reduced approximately 50% by illumination that bleaches 5 x 10(5) rhodopsin molecules/outer segments. The dark(More)
Vertebrate photoreceptor cells can signal the absorption of a single photon and then modulate their response as the intensity of the light and the intensity of the background illumination vary, and it has long been recognized that Ca2+ ions contribute to the underlying processes. Recently, several Ca(2+)-binding proteins of the EF-hand family were(More)
PURPOSE We investigated the hypothesis that visinin, a cone-specific protein first characterized in chicken retina, is a cone homologue of recoverin and may be the cancer-associated retinopathy (CAR) autoantigen in human cone cells. METHODS Visinin was purified from chicken retinas and tested for binding by CAR antisera. In addition, antibodies specific(More)
The complex sensation of vision begins with the relatively simple photoisomerization of the visual pigment chromophore 11-cis-retinal to its all-trans configuration. This event initiates a series of biochemical reactions that are collectively referred to as phototransduction, which ultimately lead to a change in the electrochemical signaling of the(More)
The role of the cytoplasmic loops and C-terminal region of bovine rhodopsin (Rho) in binding and activating rhodopsin kinase was investigated. The ability of various enzymatically truncated forms of photolyzed rhodopsin (Rho*) to stimulate rhodopsin kinase activity was quantified. Following endopeptidase Asp-N cleavage of all phosphorylation sites on the(More)
Odorant stimulation of receptor cells results in a calcium influx that activates the transduction pathway. Ca2+ acceptors, such as calmodulin, may mediate between the change in intracellular calcium and the conductance mechanism underlying the initial electrical event. Ca2+ acceptors also may participate in subsequent processing of olfactory information.(More)