Acidification of the cell wall space outside the plasma membrane is required for plant growth and is the result of proton extrusion by the plasma membrane-localized H⁺-ATPases. Here we show that the major plasma membrane proton pumps in Arabidopsis, AHA1 and AHA2, interact directly in vitro and in planta with PSY1R, a receptor kinase of the plasma membrane that serves as a receptor for the peptide growth hormone PSY1. The intracellular protein kinase domain of PSY1R phosphorylates AHA2/AHA1 at Thr-881, situated in the autoinhibitory region I of the C-terminal domain. When expressed in a yeast heterologous expression system, the introduction of a negative charge at this position caused pump activation. Application of PSY1 to plant seedlings induced rapid in planta phosphorylation at Thr-881, concomitant with an instantaneous increase in proton efflux from roots. The direct interaction between AHA2 and PSY1R observed might provide a general paradigm for regulation of plasma membrane proton transport by receptor kinases.

Item Type:	Refereed Article
Keywords:	LRR kinase, H+ pump, peptide signalling, apoplastic pH, cell elongation
Research Division:	Biological Sciences
Research Group:	Plant biology
Research Field:	Plant physiology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the biological sciences
UTAS Author:	Cuin, TA (Dr Tracey Cuin)
UTAS Author:	Shabala, S (Professor Sergey Shabala)
ID Code:	98156
Year Published:	2014
Web of Science® Times Cited:	85
Deposited By:	Tasmanian Institute of Agriculture
Deposited On:	2015-02-03
Last Modified:	2017-11-02
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