title: Breakthroughs spotlighting roles for extracellular nucleotides and apyrases in stress responses and growth and development.
abstract: Animal and plant cells release nucleotides into their extracellular matrix when touched, wounded, and when their plasma membranes are stretched during delivery of secretory vesicles and growth. These released nucleotides then function as signaling agents that induce rapid increases in the concentration of cytosolic calcium, nitric oxide and superoxide. These, in turn, are transduced into downstream physiological changes. These changes in plants include changes in the growth of diverse tissues, in gravitropism, and in the opening and closing of stomates. The concentration of extracellular nucleotides is controlled by various phosphatases, prominent among which are apyrases EC 3.6.1.5 (nucleoside triphosphate diphosphohydrolases, NTPDases). This review provides phylogenetic and pHMM analyses of plant apyrases as well as analysis of predicted post-translational modifications for Arabidopsis apyrases. This review also summarizes and discusses recent advances in research on the roles of apyrases and extracellular nucleotides in controlling plant growth and development. These include new findings that document how apyrases and extracellular nucleotides control auxin transport, modulate stomatal aperture, and mediate biotic and abiotic stress responses, and on how apyrase suppression leads to growth inhibition.
authors.affiliation: Department of Molecular Biosciences, University of Texas, Austin, TX 78713, USA.
authors.forename: Greg B
authors.initials: GB
authors.lastname: Clark
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine and University Institute of Biotechnology of Asturias, University of Oviedo, E-33006 Oviedo, Spain.
authors.forename: Reginald O
authors.initials: RO
authors.lastname: Morgan
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine and University Institute of Biotechnology of Asturias, University of Oviedo, E-33006 Oviedo, Spain.
authors.forename: Maria-Pilar
authors.initials: MP
authors.lastname: Fernandez
authors.affiliation: Department of Molecular Biosciences, University of Texas, Austin, TX 78713, USA.
authors.forename: Mari L
authors.initials: ML
authors.lastname: Salmi
authors.affiliation: Department of Molecular Biosciences, University of Texas, Austin, TX 78713, USA. Electronic address: sroux@uts.cc.utexas.edu.
authors.forename: Stanley J
authors.initials: SJ
authors.lastname: Roux
mesh_terms: D000222:Adaptation, Physiological; D015703:Antigens, CD / Q000378:metabolism; D001081:Apyrase / Q000378:metabolism*; D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism; D009711:Nucleotides / Q000378:metabolism*; D054046:Plant Stomata; D011499:Protein Processing, Post-Translational; D013312:Stress, Physiological
chemical_list: D015703:Antigens, CD; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D009711:Nucleotides; D001081:Apyrase; C067869:CD39 antigen
keywords: Apyrases; Auxin; Extracellular ATP; Phylogeny; Reactive oxygen species (ROS); Receptor