Glutathione S‐transferase π complexes with and stimulates Na+,K+‐ATPase |
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Authors: | Hideo Ochiai Hiroshi Eguchi Shunsuke Noguchi Yutaro Hayashi Hideaki Nishino Masaru Kawamura Chau H. Wu |
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Affiliation: | 1. Department of Cell Biology, School of Medicine, University of Occupational and Environmental Health, , Kitakyushu, 807‐8555 Japan;2. The Center for Student Health, Kyushu Institute of Technology, , Kitakyushu, 804‐8550 Japan;3. Hamamatsu Rosai Hospital, , Hamamatsu, 430‐8525 Japan;4. Structural Glycobiology Team, RIKEN, , Wako, 351‐0198 Japan;5. Natural Science, Fukuoka University of Education, , Munakata, 811‐4192 Japan;6. Kokura Rehabilitation College, , Kitakyushu, 800‐0206 Japan |
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Abstract: | Glutathione S‐transferase (GST) was found to complex with the Na+,K+‐ATPase as shown by binding assay using quartz crystal microbalance. The complexation was obstructed by the addition of antiserum to the α‐subunit of the Na+,K+‐ATPase, suggesting the specificity of complexation between GST and the Na+,K+‐ATPase. Co‐immunoprecipitation experiments, using the anti‐α‐subunit antiserum to precipitate the GST‐Na+,K+‐ATPase complex and then using antibodies specific to an isoform of GST to identify the co‐precipitated proteins, revealed that GSTπ was complexed with the Na+,K+‐ATPase. GST stimulated the Na+,K+‐ATPase activity up to 1.4‐fold. The level of stimulation exhibited a saturable dose–response relationship with the amount of GST added, although the level of stimulation varied depending on the content of GSTπ in the lots of GST received from supplier. The stimulation was also obtained when recombinant GSTπ was used, confirming the results. When GST was treated with reduced glutathione, GST activity was greatly stimulated, whereas the level of stimulation of the Na+,K+‐ATPase activity was similar to that when untreated GST was added. When GST was treated with H2O2, GST activity was greatly diminished while the stimulation of the Na+,K+‐ATPase activity was preserved. The results suggest that GSTπ complexes with the Na+,K+‐ATPase and stimulates the latter independent of its GST activity. Copyright © 2012 John Wiley & Sons, Ltd. |
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Keywords: | Na+,K+‐ATPase glutathione S‐transferase stimulation |
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