Peptidyl‐prolylcis‐transisomerase ROF2 modulates intracellular pH homeostasis in Arabidopsis

• DOI: 10.1111/j.1365-313x.2012.04921.x
• Publication Date: 2012-01-23T12:49:54Z
• Authors: Gaetano Bissoli; Regina Niñoles; Sandra Fresquet; Samuela Palombieri; Eduardo Bueso; Lourdes Rubio; María J. García‐S...; José A. Fernández; José M. Mulet; Ramón Serrano
• Keywords: 0301 basic medicine; Hot Temperature; Arabidopsis thaliana; H plus-ATPase; Stress tolerance; Arabidopsis; Intracellular Space; K plus transport; 03 medical and health sciences; Gene Expression Regulation, Plant; BIOQUIMICA Y BIOLOGIA MOLECULAR; Homeostasis; Toxic cations; toxic cations; Heat-Shock Proteins; Membrane potential; Oligonucleotide Array Sequence Analysis; stress tolerance; Arabidopsis Proteins; Reverse Transcriptase Polymerase Chain Reaction; Cell Membrane; Gene Expression Regulation, Developmental; Biological Transport; K+ transport; Hydrogen-Ion Concentration; Peptidylprolyl Isomerase; Plants, Genetically Modified; Rubidium; Proton-Translocating ATPases; Mutation; Potassium; H+-ATPase; membrane potential; Protons

SummaryIntracellular pH must be kept close to neutrality to be compatible with cellular functions, but the mechanisms of pH homeostasis and the responses to intracellular acidification are mostly unknown. In the plantArabidopsis thaliana, we found that intracellular acid stress generated by weak organic acids at normal external pH induces expression of several chaperone genes, includingROF2, which encodes a peptidyl‐prolylcis‐transisomerase of the FK506‐binding protein class. Loss of function ofROF2, and especially double mutation ofROF2and the closely related geneROF1, results in acid sensitivity. Over‐expression ofROF2confers tolerance to intracellular acidification by increasing proton extrusion from cells. The activation of the plasma membrane proton pump (H+‐ATPase) is indirect: over‐expression ofROF2activates K+uptake, causing depolarization of the plasma membrane, which activates the electrogenic H+pump. The depolarization ofROF2over‐expressing plants explains their tolerance to toxic cations such as lithium, norspermidine and hygromycin B, whose uptake is driven by the membrane potential. AsROF2induction and intracellular acidification are common consequences of many stresses, this mechanism of pH homeostasis may be of general importance for stress tolerance.