Header

UZH-Logo

Maintenance Infos

The Protein Phosphatases ATUNIS1 and ATUNIS2 Regulate Cell Wall Integrity in Tip-Growing Cells


Franck, Christina Maria; Westermann, Jens; Bürssner, Simon; Lentz, Roswitha; Lituiev, Dmytro Sergiiovych; Boisson-Dernier, Aurélien (2018). The Protein Phosphatases ATUNIS1 and ATUNIS2 Regulate Cell Wall Integrity in Tip-Growing Cells. Plant Cell, 30(8):1906-1923.

Abstract

Fast tip-growing plant cells such as pollen tubes (PTs) and root hairs (RHs) require a robust coordination between their internal growth machinery and modifications of their extracellular rigid, yet extensible, cell wall (CW). Part of this essential coordination is governed by members of the Catharanthus roseus receptor-like kinase1-like (CrRLK1L) subfamily of RLKs with FERONIA (FER) and its closest homologs, ANXUR1 (ANX1) and ANX2, controlling CW integrity during RH and PT growth, respectively. Recently, Leucine-Rich Repeat Extensin 8 (LRX8) to LRX11 were also shown to be important for CW integrity in PTs. We previously reported an anx1 anx2 suppressor screen in Arabidopsis thaliana that revealed MARIS (MRI) as a positive regulator of both FER- and ANX1/2-dependent CW integrity pathways. Here, we characterize a suppressor that exhibits a weak rescue of the anx1 anx2 PT bursting phenotype and a short RH phenotype. The corresponding suppressor mutation causes a D94N substitution in a Type One Protein Phosphatase we named ATUNIS1 (AUN1). We show that AUN1 and its closest homolog, AUN2, are nucleocytoplasmic negative regulators of tip growth. Moreover, we demonstrate that AUN1D94N and AUN1H127A harboring mutations in key amino acids of the conserved catalytic site of phosphoprotein phosphatases function as dominant amorphic variants that repress PT growth. Finally, genetic interaction studies using the hypermorph MRIR240C and amorph AUN1D94N dominant variants indicate that LRX8-11 and ANX1/2 function in distinct but converging pathways to fine-tune CW integrity during tip growth.

Abstract

Fast tip-growing plant cells such as pollen tubes (PTs) and root hairs (RHs) require a robust coordination between their internal growth machinery and modifications of their extracellular rigid, yet extensible, cell wall (CW). Part of this essential coordination is governed by members of the Catharanthus roseus receptor-like kinase1-like (CrRLK1L) subfamily of RLKs with FERONIA (FER) and its closest homologs, ANXUR1 (ANX1) and ANX2, controlling CW integrity during RH and PT growth, respectively. Recently, Leucine-Rich Repeat Extensin 8 (LRX8) to LRX11 were also shown to be important for CW integrity in PTs. We previously reported an anx1 anx2 suppressor screen in Arabidopsis thaliana that revealed MARIS (MRI) as a positive regulator of both FER- and ANX1/2-dependent CW integrity pathways. Here, we characterize a suppressor that exhibits a weak rescue of the anx1 anx2 PT bursting phenotype and a short RH phenotype. The corresponding suppressor mutation causes a D94N substitution in a Type One Protein Phosphatase we named ATUNIS1 (AUN1). We show that AUN1 and its closest homolog, AUN2, are nucleocytoplasmic negative regulators of tip growth. Moreover, we demonstrate that AUN1D94N and AUN1H127A harboring mutations in key amino acids of the conserved catalytic site of phosphoprotein phosphatases function as dominant amorphic variants that repress PT growth. Finally, genetic interaction studies using the hypermorph MRIR240C and amorph AUN1D94N dominant variants indicate that LRX8-11 and ANX1/2 function in distinct but converging pathways to fine-tune CW integrity during tip growth.

Statistics

Citations

Dimensions.ai Metrics
14 citations in Web of Science®
14 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

2 downloads since deposited on 27 Feb 2019
0 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Plant and Microbial Biology
07 Faculty of Science > Zurich-Basel Plant Science Center
Dewey Decimal Classification:580 Plants (Botany)
Scopus Subject Areas:Life Sciences > Plant Science
Life Sciences > Cell Biology
Uncontrolled Keywords:Plant Science, Cell Biology
Language:English
Date:1 August 2018
Deposited On:27 Feb 2019 13:08
Last Modified:29 Jul 2020 09:44
Publisher:American Society of Plant Biologists
ISSN:1040-4651
OA Status:Closed
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1105/tpc.18.00284

Download

Closed Access: Download allowed only for UZH members