The catalytic subunit of phosphatase 2A dephosphorylates phosphoopsin
| Autor: | Krzysztof Palczewski, Paul A. Hargrave, T. S. Ingebritsen, J.H. McDowell |
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| Rok vydání: | 1989 |
| Předmět: |
G-Protein-Coupled Receptor Kinase 1
Macromolecular Substances Protein subunit Phosphatase Biochemistry Dephosphorylation Protein Phosphatase 1 Phosphoprotein Phosphatases Animals Phosphorylase a Photoreceptor Cells Protein Phosphatase 2 Eye Proteins Chromatography High Pressure Liquid biology Chemistry Rod Opsins Protein phosphatase 1 Rod Cell Outer Segment Protein phosphatase 2 Chromatography Ion Exchange Phosphoproteins Kinetics Rhodopsin Chromatography Gel biology.protein Cattle Protein Kinases Visual phototransduction |
| Zdroj: | Biochemistry. 28:415-419 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi00428a001 |
| Popis: | Rod cell outer segments were found to contain a protein phosphatase activity toward phosphoopsin with properties very similar to those of protein phosphatase 1 or 2A. The opsin phosphatase activity was stable to ethanol precipitation, had a Mr of 35,000-38,000 as determined by gel filtration, and was not dependent on divalent cations for activity. The chromatographic properties on DEAE-cellulose of the rod outer segment protein phosphatase were also similar to those reported for protein phosphatase 1 or 2A. In order to distinguish between these two protein phosphatases, we tested homogeneous preparations of protein phosphatases 1 and 2A from skeletal muscle for activity toward phosphoopsin. Protein phosphatase 2A dephosphorylated phosphoopsin at approximately 10% of its rate toward phosphorylase a, whereas protein phosphatase 1 had no activity toward phosphoopsin. We conclude that protein phosphatase 2A is present in the rod cell outer segment and that it is a likely candidate to perform the in vivo dephosphorylation of rhodopsin in the visual cycle. |
| Databáze: | OpenAIRE |
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