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Mutation of a Conserved Motif of PP2C.D Phosphatases Confers SAUR Immunity and Constitutive Activity by Wong, Jeh Haur; Spartz, Angela K.; Park, Mee Yeon; Du, Minmin; Gray, William M. is a Agricultural and Biological Sciences article available to read on EtoBox.

What is Mutation of a Conserved Motif of PP2C.D Phosphatases Confers SAUR Immunity and Constitutive Activity about?

The phytohormone auxin promotes the growth of plant shoots by stimulating cell expansion via plasma membrane (PM) H-ATPase activation, which facilitates cell wall loosening and solute uptake. Mechanistic insight was recently obtained by demonstrating that auxin-induced SMALL AUXIN UP RNA (SAUR) proteins inhibit D-CLADE TYPE 2C PROTEIN PHOSPHATASE (PP2C.D) activity, thereby trapping PM H-ATPases in the phosphorylated, activated state, but how SAURs bind PP2C.D proteins and inhibit their activity is unknown. Here, we identified a highly conserved motif near the C-terminal region of the PP2C.D catalytic domain that is required for SAUR binding in Arabidopsis (). Missense mutations in this motif abolished SAUR binding but had no apparent effect on catalytic activity. Consequently, mutant PP2C.D proteins that could not bind SAURs exhibited constitutive activity, as they were immune to SAUR inhibition. In planta expression of SAUR-immune or derivatives conferred severe cell expansion defects and corresponding constitutively low levels of PM H-ATPase phosphorylation. These growth defects were not alleviated by either auxin treatment or 35S:StrepII-SAUR19 coexpression. In contrast, a PM H-

Who reads Mutation of a Conserved Motif of PP2C.D Phosphatases Confers SAUR Immunity and Constitutive Activity?

Author

Wong, Jeh Haur; Spartz, Angela K.; Park, Mee Yeon; Du, Minmin; Gray, William M.

Publisher

American Society of Plant Biologists; American Society of Plant Biologists (ASPB); Oxford University Press (OUP) (ISSN 0032-0889)

Published

2019

Language

EN

Field

Agricultural and Biological Sciences (Life Sciences)