Journal article
Calcium-sensor proteins but not bicarbonate ion activate retinal photoreceptor membrane guanylyl cyclase in photoreceptors
Frontiers in molecular neuroscience, v 17, 1509366
09 Dec 2024
PMID: 39717564
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Retinal membrane guanylyl cyclase (RetGC), regulated by guanylyl cyclase activating proteins (GCAPs) via negative calcium-feedback, is one of the most critically important enzymes in vertebrate rod and cone physiology, enabling their sensitivity to light. It was also reported that, similarly to olfactory receptor guanylyl cyclase, bicarbonate anion directly stimulates RetGC activity in photoreceptors as a novel phototransduction-linked regulating factor. We directly tested whether or not RetGC is a bicarbonate-activated enzyme using recombinant human RetGC expressed in HEK293 cells and the native RetGC in mouse retinas. Whereas RetGC in all cases was activated by GCAPs, we found no evidence indicating that bicarbonate can produce direct stimulating effect on RetGC catalytic activity, either basal or GCAP-activated, even at concentrations as high as 100 mM. Instead, near-physiological concentrations of bicarbonate only slightly reduced RetGC activity, whereas concentrations substantially exceeding physiological levels caused a more pronounced reduction of RetGC activity measured in mouse retinas. Our results argue that photoreceptor guanylyl cyclase is not a bicarbonate-stimulated enzyme and rule out the possibility that effects of bicarbonate on photoreceptor physiology are mediated by a direct stimulation of retinal guanylyl cyclase by HCO
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Details
- Title
- Calcium-sensor proteins but not bicarbonate ion activate retinal photoreceptor membrane guanylyl cyclase in photoreceptors
- Creators
- Igor V. Peshenko - Salus UniversityElena V. Olshevskaya - Salus UniversityAlexander M. Dizhoor - Salus University
- Publication Details
- Frontiers in molecular neuroscience, v 17, 1509366
- Publisher
- Frontiers Media
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Neurobiology and Anatomy; Pennsylvania College of Optometry (PCO)
- Web of Science ID
- WOS:001382042800001
- Scopus ID
- 2-s2.0-85212669930
- Other Identifier
- 991022035113804721
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- Web of Science research areas
- Neurosciences