The signal metabolite trehalose‐6‐phosphate inhibits the sucrolytic activity of sucrose synthase from developing castor beans

• Published in: FEBS letters Vol. 592; no. 15; pp. 2525 - 2532
• Main Authors: Fedosejevs, Eric T., Feil, Regina, Lunn, John E., Plaxton, William C.
• Format: Journal Article
• Language: English
• Published: England 01-08-2018
• Subjects: allosteric inhibition; Feedback, Physiological - drug effects; Glucosyltransferases - metabolism; Glycolysis - drug effects; Metabolic Networks and Pathways - drug effects; Plant Development - physiology; Ricinus communis (castor oil plant); Ricinus communis - enzymology; Ricinus communis - growth & development; Ricinus communis - metabolism; sink strength; Sucrose - metabolism; sucrose synthase; Sugar Phosphates - pharmacology; Sugar Phosphates - physiology; Trehalose - analogs & derivatives; Trehalose - metabolism; Trehalose - pharmacology; Trehalose - physiology; trehalose‐6‐phosphate; allosteric inhibition; Ricinus communis (castor oil plant); sink strength; trehalose-6-phosphate; sucrose synthase
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1002/1873-3468.13197

In plants, trehalose 6‐phosphate (T6P) is a key signaling metabolite that functions as both a signal and negative feedback regulator of sucrose levels. The mode of action by which T6P senses and regulates sucrose is not fully understood. Here, we demonstrate that the sucrolytic activity of RcSUS1, the dominant sucrose synthase isozyme expressed in developing castor beans, is allosterically inhibited by T6P. The feedback inhibition of SUS by T6P may contribute to the control of sink strength and sucrolytic flux in heterotrophic plant tissues.