Visual arrestin in Limulus is phosphorylated at multiple sites in the light and in the dark.
Arrestins participate in the termination of phototransduction in both vertebrates and invertebrates. However, the visual arrestins of invertebrates and vertebrates differ significantly from one another in that the invertebrate visual arrestins become phosphorylated rapidly in response to light while those in the photoreceptors of vertebrates do not. In an effort to understand the functional relevance of arrestin phosphorylation, we examined this process in the photoreceptors of the horseshoe crab Limulus polyphemus. We report that Limulus visual arrestin can be phosphorylated at three sites near its C-terminus and show that arrestin molecules phosphorylated on one, two, and three sites are normally present in both light- and dark-adapted photoreceptors. Light adaptation increases the amount of arrestin phosphorylated at three sites.
Battelle
B A
BA
Department of Neuroscience, University of Florida, St. Augustine 32080, USA. Battelle@whitney.ufl.edu
Andrews
A W
AW
Kempler
K E
KE
Edwards
S C
SC
Smith
W C
WC
D000221:Adaptation, Ocular / Q000502:physiology*; D000818:Animals; D000918:Antibody Specificity; D019393:Arrestin / Q000378:metabolism*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D003623:Dark Adaptation / Q000502:physiology*; D006737:Horseshoe Crabs / Q000166:cytology / Q000378:metabolism*; D010766:Phosphorylation; D017956:Photoreceptor Cells, Invertebrate / Q000166:cytology / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D014785:Vision, Ocular / Q000502:physiology*
D019393:Arrestin; D020033:Protein Isoforms; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases