LOCALIZATION OF GUANYLATE CYCLASE-ACTIVATING PROTEIN-2 IN MAMMALIAN RETINAS

Citation
A. Ottobruc et al., LOCALIZATION OF GUANYLATE CYCLASE-ACTIVATING PROTEIN-2 IN MAMMALIAN RETINAS, Proceedings of the National Academy of Sciences of the United Statesof America, 94(9), 1997, pp. 4727-4732
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Multidisciplinary Sciences
ISSN journal
0027-8424
Volume
94
Issue
9
Year of publication
1997
Pages
4727 - 4732
Database
ISI
SICI code
0027-8424(1997)94:9<4727:LOGCPI>2.0.ZU;2-#
Abstract
Guanylate cyclase-activating proteins (GCAP1 and GCAP2) are thought to mediate the intracellular stimulation of guanylate cyclase (GC) by Ca 2+, a key event in recovery of the dark state of rod photoreceptors af ter exposure to light, GCAP1 has been localized to rod and cone outer segments, the sites of phototransduction, and to photoreceptor synapti c terminals and some cone somata, We used in situ hybridization and im munocytochemistry to localize GCAP2 in human, monkey, and bovine retin as, In human and monkey retinas, the most intense immunolabeling with anti-GCAP2 antibodies was in the cone inner segments, somata, and syna ptic terminals and, to a lesser degree, in rod inner segments and inne r retinal neurons. In bovine retina, the most intense immunolabeling w as in the rod inner segments, with weaker labeling of cone myoids, som ata, and synapses, By using a GCAP2-specific antibody in enzymatic ass ays,we confirmed that GCAP1 but not GCAP2 is the major component that stimulates GC in bovine rod outer segment homogenates, These results s uggest that although GCAP1 is involved in the Ca2+-sensitive regulatio n of GC in rod and cone outer segments, GCAP2 may have non-phototransd uction functions in photoreceptors and inner retinal neurons.