CBL1-CIPK26-mediated phosphorylation enhances activity of the NADPH oxidase RBOHC, but is dispensable for root hair growth

FEBS Lett. 2018 Aug;592(15):2582-2593. doi: 10.1002/1873-3468.13187. Epub 2018 Aug 1.

Abstract

Root hairs (RH) are tip growing polarized cells aiding the uptake of nutrients and water into plants. RH differentiation involves the interplay of various hormones and second messengers. Tightly regulated production of reactive oxygen species by the NADPH oxidase RBOHC crucially functions in RH differentiation and Ca2+ -dependent phosphorylation has been implemented in these processes. However, the kinases regulating RBOHC remained enigmatic. Here we identify CBL1-CIPK26 Ca2+ sensor-kinase complexes as modulators of RBOHC activity. Combined genetic, cell biological and biochemical analyses reveal synergistic function of CIPK26-mediated phosphorylation and Ca2+ binding for RBOHC activation. Complementation of rbohC mutant RH phenotypes by a S318/322 phosphorylation deficient RBOHC version suggests flexible and alternating phosphorylation patterns as mechanism fine-tuning ROS production in RH development.

Keywords: calcium; reactive oxygen species; root hair growth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Arabidopsis* / genetics
  • Arabidopsis* / growth & development
  • Arabidopsis* / metabolism
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism*
  • Genetic Complementation Test
  • Mutation, Missense
  • NADPH Oxidases* / chemistry
  • NADPH Oxidases* / genetics
  • NADPH Oxidases* / metabolism
  • Phosphorylation
  • Plant Roots / genetics
  • Plant Roots / growth & development*
  • Plant Roots / metabolism
  • Plants, Genetically Modified
  • Protein Interaction Domains and Motifs / genetics
  • Protein Kinases / genetics
  • Protein Kinases / metabolism*
  • Reactive Oxygen Species / metabolism

Substances

  • Arabidopsis Proteins
  • Calcium-Binding Proteins
  • Reactive Oxygen Species
  • calcineurin B-like protein 1, Arabidopsis
  • respiratory burst oxidase homolog D, Arabidopsis
  • NADPH Oxidases
  • CIPK26 protein, Arabidopsis
  • Protein Kinases