A phosphothreonine residue at the C-terminal end of the plasma membrane H+-ATPase is protected by fusicoccin-induced 14-3-3 binding.
We have isolated the plasma membrane H+-ATPase in a phosphorylated form from spinach (Spinacia oleracea L.) leaf tissue incubated with fusicoccin, a fungal toxin that induces irreversible binding of 14-3-3 protein to the C terminus of the H+-ATPase, thus activating H+ pumping. We have identified threonine-948, the second residue from the C-terminal end of the H+-ATPase, as the phosphorylated amino acid. Turnover of the phosphate group of phosphothreonine-948 was inhibited by 14-3-3 binding, suggesting that this residue may form part of a binding motif for 14-3-3. This is the first identification to our knowledge of an in vivo phosphorylation site in the plant plasma membrane H+-ATPase.
Department of Plant Biochemistry, Lund University, P.O. Box 117, SE-221 00 Lund, Sweden. anne.olsson@plantbio.lu.se
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Olsson
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Svennelid
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Ek
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Sommarin
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Larsson
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000201:enzymology; D006027:Glycosides / Q000494:pharmacology*; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D010769:Phosphothreonine / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D018724:Spinacia oleracea; D014446:Tyrosine 3-Monooxygenase
D048948:14-3-3 Proteins; D006027:Glycosides; D010761:Phosphorus Radioisotopes; D011506:Proteins; D010769:Phosphothreonine; C007808:fusicoccin; D014446:Tyrosine 3-Monooxygenase; D006180:Proton-Translocating ATPases