title: Pharmacological analysis of nod factor-induced calcium spiking in Medicago truncatula. Evidence for the requirement of type IIA calcium pumps and phosphoinositide signaling.
abstract: Bacterial Nod factors trigger a number of cellular responses in root hairs of compatible legume hosts, which include periodic, transient increases in cytosolic calcium levels, termed calcium spiking. We screened 13 pharmaceutical modulators of eukaryotic signal transduction for effects on Nod factor-induced calcium spiking. The purpose of this screening was 2-fold: to implicate enzymes required for Nod factor-induced calcium spiking in Medicago sp., and to identify inhibitors of calcium spiking suitable for correlating calcium spiking to other Nod factor responses to begin to understand the function of calcium spiking in Nod factor signal transduction. 2-Aminoethoxydiphenylborate, caffeine, cyclopiazonic acid (CPA), 2,5-di-(t-butyl)-1,4-hydroquinone, and U-73122 inhibit Nod factor-induced calcium spiking. CPA and U-73122 are inhibitors of plant type IIA calcium pumps and phospholipase C, respectively, and implicate the requirement for these enzymes in Nod factor-induced calcium spiking. CPA and U-73122 inhibit Nod factor-induced calcium spiking robustly at concentrations with no apparent toxicity to root hairs, making CPA and U-73122 suitable for testing whether calcium spiking is causal to subsequent Nod factor responses.
authors.affiliation: Howard Hughes Medical Institute, Department of Biological Sciences, Stanford University, Stanford, CA 94305-5020, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Engstrom
authors.forename: David W
authors.initials: DW
authors.lastname: Ehrhardt
authors.forename: Raka M
authors.initials: RM
authors.lastname: Mitra
authors.forename: Sharon R
authors.initials: SR
authors.lastname: Long
mesh_terms: D001896:Boron Compounds / Q000494:pharmacology; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004963:Estrenes / Q000494:pharmacology; D006873:Hydroquinones / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D029902:Medicago / Q000187:drug effects* / Q000378:metabolism; D015394:Molecular Structure; D010716:Phosphatidylinositols / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects* / Q000378:metabolism; D011760:Pyrrolidinones / Q000494:pharmacology; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D001896:Boron Compounds; D002121:Calcium Channel Blockers; D004963:Estrenes; D006873:Hydroquinones; D007211:Indoles; D008070:Lipopolysaccharides; C092736:Nod factor, Rhizobium leguminosarum; D010716:Phosphatidylinositols; D011760:Pyrrolidinones; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C019359:2,5-di-tert-butylhydroquinone; D002110:Caffeine; C109986:2-aminoethoxydiphenyl borate; D010738:Type C Phospholipases; D000252:Calcium-Transporting ATPases; D002118:Calcium; C000543:cyclopiazonic acid