Abstract
Band 3, the major transmembrane multifunctional protein of human erythrocytes, has been found to be phosphorylated-dephosphorylated on both Ser/Thr- and Tyr-residues by specific protein kinases and protein phosphatases. The results reported here would indicate that the ghosts prepared from human erythrocytes pretreated with DIDS, well known inhibitor of band 3-mediated anion transport, exhibit a markedly reduced Ser/Thr-phosphorylation of spectrin and band 3, when incubated with [gamma-32P]ATP in the presence of Mg2+. On the other hand, Tyr-phosphorylation of this latter protein is practically unchanged or even slightly enhanced. This suggests that Ser/Thr- and Tyr-phosphorylation of band 3 display a different functional role.
MeSH terms
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4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
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4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / analogs & derivatives*
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4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / pharmacology
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Anion Exchange Protein 1, Erythrocyte / chemistry
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Anion Exchange Protein 1, Erythrocyte / drug effects
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Anion Exchange Protein 1, Erythrocyte / metabolism
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Binding Sites
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Erythrocyte Membrane / drug effects*
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Erythrocyte Membrane / metabolism
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Humans
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In Vitro Techniques
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Membrane Proteins / blood
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Membrane Proteins / chemistry
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Membrane Proteins / drug effects*
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Phosphorylation
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Serine / chemistry
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Spectrin / chemistry
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Spectrin / drug effects
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Spectrin / metabolism
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Threonine / chemistry
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Tyrosine / chemistry
Substances
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Anion Exchange Protein 1, Erythrocyte
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Membrane Proteins
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Spectrin
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4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
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Threonine
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Tyrosine
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Serine
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4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid