14-3-3 proteins control proteolysis of nitrate reductase in spinach leaves.
To test a possible role of 14-3-3 proteins in the degradation of nitrate reductase (NR) in leaves, we monitored 14-3-3s bound to NR in leaf extracts. The amount of 14-3-3s that coimmunoprecipitated with serine 543 phospho-NR (p-NR) increased upon a light/dark transition. This was accompanied by a similar increase in the protein turnover rate of NR in leaves. Purified NR was degraded in extracts from darkened but not from illuminated leaves. Removal of 14-3-3s from such extracts prevented NR degradation. We conclude that the availability of 14-3-3s for p-NR regulates the stability of NR.
Weiner
H
H
Julius-von-Sachs-Institut für Biowissenschaften, Lehrstuhl Botanik I, Molekulare Pflanzenphysiologie und Biophysik, Würzburg, Germany. weiner@botanik.uni-wuerzburg.de
Kaiser
W M
WM
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D003624:Darkness; D004795:Enzyme Stability; D006868:Hydrolysis; D007700:Kinetics; D008027:Light; D008969:Molecular Sequence Data; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000378:metabolism*; D018515:Plant Leaves / Q000201:enzymology; D011485:Protein Binding; D011506:Proteins / Q000502:physiology*; D018724:Spinacia oleracea / Q000201:enzymology*; D014446:Tyrosine 3-Monooxygenase
D048948:14-3-3 Proteins; D011506:Proteins; D014446:Tyrosine 3-Monooxygenase; D009565:Nitrate Reductases; D050901:Nitrate Reductase