Phosducin and betagamma-transducin interaction I: effects of post-translational modifications.
The interaction between phosducin and betagamma-transducin plays regulatory roles in light adaptation of photoreceptors. Both phosducin and betagamma-transducin undergo post-translational modifications, with phosducin modified by phosphorylation and the gamma subunit of betagamma-transducin by farnesylation and carboxylmethylation. In this study we exploited the electrophoretic mobilities of these native proteins to develop a micro binding assay and examined the effects of post-translational modifications on binding affinities. It was found that decarboxylmethylation of gamma-transducin increased the mobility of betagamma-transducin during native gel electrophoresis, but decreased the apparent affinity for phosducin by about 2-fold. Phosphorylation of phosducin by protein kinase A increased the mobility but decreased the apparent affinity for betagamma-transducin by at least 3-fold.
Chen
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F
Department of Neurobiology, UCLA School of Medicine, Los Angeles, California 90095, USA.
Lee
R H
RH
D000818:Animals; D002264:Carboxylic Acids / Q000378:metabolism; D002417:Cattle; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005136:Eye Proteins / Q000378:metabolism*; D020555:GTP-Binding Protein Regulators; D008745:Methylation; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D017368:Protein Prenylation; D011499:Protein Processing, Post-Translational; D015293:Transducin / Q000378:metabolism*
D002264:Carboxylic Acids; D005136:Eye Proteins; D020555:GTP-Binding Protein Regulators; D010750:Phosphoproteins; C065631:phosducin; D011494:Protein Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D015293:Transducin