Purification and phosphorylation of the effector protein NopL from Rhizobium sp. NGR234.
Bacterial pathogens use type III secretion systems (TTSSs) to deliver virulence factors into eukaryotic cells. These effectors perturb host-defence responses, especially signal transduction pathways. A functional TTSS was identified in the symbiotic, nitrogen-fixing bacterium Rhizobium sp. NGR234. NopL (formerly y4xL) of NGR234 is a putative symbiotic effector that modulates nodulation in legumes. To test whether NopL could interact with plant proteins, in vitro phosphorylation experiments were performed using recombinant nopL protein purified from Escherichia coli as well as protein extracts from Lotus japonicus and tobacco plants. NopL serves as a substrate for plant protein kinases as well as purified protein kinase A. Phosphorylation of NopL was inhibited by the Ser/Thr kinase inhibitor K252a as well as by PD98059, a mitogen-activated protein (MAP) kinase kinase inhibitor. It thus seems likely that, after delivery into the plant cell, NopL modulates MAP kinase pathways.
Bartsev
Alexander V
AV
Laboratorie de Biologie Moléculaire des Plantes Supérieures, Université de Genève, 1 chemin de l'Impératrice, 1292 Chambésy, Geneva, Switzerland.
Boukli
Nawal M
NM
Deakin
William J
WJ
Staehelin
Christian
C
Broughton
William J
WJ
D001345:Autoradiography / Q000379:methods; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000737:chemistry / Q000378:metabolism; D015151:Immunoblotting; D007700:Kinetics; D000070116:Lotus / Q000201:enzymology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012231:Rhizobium / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D014026:Nicotiana / Q000201:enzymology
D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D010761:Phosphorus Radioisotopes; D010940:Plant Proteins; D011994:Recombinant Proteins; D017346:Protein Serine-Threonine Kinases; D020928:Mitogen-Activated Protein Kinases