Arabidopsis MAP-Kinase 3 Phosphorylates UDP-Glucose Dehydrogenase: a Key Enzyme Providing UDP-Sugar for Cell Wall Biosynthesis.

ABSTRACT: The enzyme UDP-glucose dehydrogenase (UGD) competes with sucrose-phosphate synthase for the common photosynthesis product UDP-glucose. Sucrose-phosphate synthase is part of a pathway for the export of sucrose from source leaves to neighboring cells or the phloem. UGD is a central enzyme in a pathway for many nucleotide sugars used in local cell wall biosynthesis. Here, we identify a highly conserved phosphorylation site in UGD which is readily phosphorylated by MAP-kinase 3 in Arabidopsis. Phosphorylation occurs at a surface-exposed extra loop in all plant UGDs that is absent in UGDs from bacteria or animals. Phosphorylated sucrose-phosphate synthase is shifted to an inactive form which we did not measure for phosphorylated UGD. Plant UGDs have an extra loop which is phosphorylated by AtMP

SUBMITTER: Kohlberger M 

PROVIDER: S-EPMC6404385 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature