Site-specific regulatory interaction between spinach leaf sucrose-phosphate synthase and 14-3-3 proteins

• Published in: FEBS letters 1998-09, Vol.435 (1), p.110-114
• Main Authors: Toroser, Dikran, Athwal, Gurdeep S., Huber, Steven C.
• Format: Article
• Language: English
• Subjects: 14-3-3 protein; 14-3-3 Proteins; AICAR, 5-aminoimidazole-4-carboxamide ribonucleoside; Amino Acid Sequence; Aminoimidazole Carboxamide - analogs & derivatives; Aminoimidazole Carboxamide - pharmacology; Binding Sites; Enzyme Activation - drug effects; Enzyme Inhibitors - metabolism; Enzyme Inhibitors - pharmacology; Glucosyltransferases - drug effects; Glucosyltransferases - metabolism; Life Sciences (General); MAbs, monoclonal antibodies; Magnesium - metabolism; Molecular Sequence Data; Peptide Fragments - metabolism; Phosphorylation; Plant Leaves - drug effects; Plant Leaves - enzymology; Protein:protein interaction; Proteins - metabolism; Proteins - pharmacology; Ribonucleotides - pharmacology; RU, response units; Serine - metabolism; Space life sciences; Spinach; Spinacia oleracea - drug effects; Spinacia oleracea - enzymology; SPR, surface plasmon resonance; SPS, sucrose-phosphate synthase; Sucrose-phosphate synthase; Surface plasmon resonance; Tyrosine 3-Monooxygenase; ZMP, 5-aminoimidazole-4-carboxamide ribonucleoside monophosphate
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(98)01048-5

We report an Mg 2+-dependent interaction between spinach leaf sucrose-phosphate synthase (SPS) and endogenous 14-3-3 proteins, as evidenced by co-elution during gel filtration and co-immunoprecipitation. The content of 14-3-3s associated with an SPS immunoprecipitate was inversely related to activity, and was specifically reduced when tissue was pretreated with 5-aminoimidazole-4-carboxamide riboside, suggesting metabolite control in vivo. A synthetic phosphopeptide based on Ser-229 was shown by surface plasmon resonance to bind a recombinant plant 14-3-3, and addition of the phosphorylated SPS-229 peptide was found to stimulate the SPS activity of an SPS:14-3-3 complex. Taken together, the results suggest a regulatory interaction of 14-3-3 proteins with Ser-229 of SPS.