title: Molecular cloning and localization of rhodopsin kinase in the mammalian pineal.
abstract: Several retinal photoreceptor proteins involved in phototransduction have also been found in the mammalian pineal. This study demonstrates that rat and human pineals express protein kinases that are identical to the corresponding rod photoreceptor rhodopsin kinases. The deduced amino acid sequence of rat and human rhodopsin kinases have 84% sequence similarity to the earlier reported sequence of the bovine retinal enzyme, with complete conservation of the topological regions containing the position of the catalytic domain and sites of posttranslational modifications. Rat pineal also expresses rod opsin and putative blue cone opsin. Using immunocytochemistry, rod opsin and rhodopsin kinase were found to be co-localized in pinealocytes in the human tissue. These data demonstrate that the mammalian pineal contains light-sensitive opsins and a kinase involved in their inactivation. These findings correlate with an earlier report that neonatal rats show extraretinal light sensitivity, and suggest that a functional photoreceptive system may be present in the adult mammalian pineal.
authors.affiliation: Department of Ophthalmology, University of Washington, Seattle 98195-6485, USA.
authors.forename: X
authors.initials: X
authors.lastname: Zhao
authors.forename: F
authors.initials: F
authors.lastname: Haeseleer
authors.forename: R N
authors.initials: RN
authors.lastname: Fariss
authors.forename: J
authors.initials: J
authors.lastname: Huang
authors.forename: W
authors.initials: W
authors.lastname: Baehr
authors.forename: A H
authors.initials: AH
authors.lastname: Milam
authors.forename: K
authors.initials: K
authors.lastname: Palczewski
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003001:Cloning, Molecular; D017931:DNA Primers; D015342:DNA Probes / Q000737:chemistry; D018076:DNA, Complementary / Q000032:analysis; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D051606:G-Protein-Coupled Receptor Kinase 1; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D010870:Pineal Gland / Q000166:cytology / Q000201:enzymology*; D016133:Polymerase Chain Reaction; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017299:Rod Opsins / Q000235:genetics / Q000378:metabolism
chemical_list: D017931:DNA Primers; D015342:DNA Probes; D018076:DNA, Complementary; D005136:Eye Proteins; D012333:RNA, Messenger; D017299:Rod Opsins; C095853:short-wavelength opsin; D011494:Protein Kinases; D051606:G-Protein-Coupled Receptor Kinase 1; C496764:GRK1 protein, human; C496765:Grk1 protein, rat