Back to Search
Start Over
ATP binding is required for physiological activation of retinal guanylate cyclase.
- Source :
-
Biochemical and biophysical research communications [Biochem Biophys Res Commun] 2005 Dec 16; Vol. 338 (2), pp. 1291-8. Date of Electronic Publication: 2005 Oct 24. - Publication Year :
- 2005
-
Abstract
- ATP bound to retinal guanylate cyclase (retGC)/membranes prior to the assay (pre-binding effect) and during the assay (direct effect) further enhances retGC activity stimulated by GC-activating proteins (GCAPs). Here we investigate differences between these two effects. We found that the pre-binding effect, but not the direct effect, was absent in membranes pre-washed with Mg(2+)-free hypotonic buffers, that the pre-binding effect, but not the direct effect, was strictly limited to GCAP-stimulated retGC activity, and that these two effects were independent and additive rather than being synergistic. Pre-incubation with amiloride enhanced GCAP2-activated retGC activity in a manner similar to that by ATP pre-binding; however, amiloride did not directly stimulate the retGC activity. These results indicate that these two effects are mechanistically different. Levels of retGC activation by these effects and conditions required for these effects indicate that only the mechanism involving ATP pre-binding is physiologically relevant to retGC activation.
Details
- Language :
- English
- ISSN :
- 0006-291X
- Volume :
- 338
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Biochemical and biophysical research communications
- Publication Type :
- Academic Journal
- Accession number :
- 16259948
- Full Text :
- https://doi.org/10.1016/j.bbrc.2005.10.087