Negative feedback regulation of microbe-associated molecular pattern-induced cytosolic Ca2+ transients by protein phosphorylation.
Microbe/pathogen-associated molecular patterns (MAMPs/PAMPs) often induce rises in cytosolic free Ca(2+) concentration ([Ca(2+)](cyt)) and protein phosphorylation. Though they are postulated to play pivotal roles in plant innate immunity, their molecular links and the regulatory mechanisms remain largely unknown. To investigate the regulatory mechanisms for MAMP-induced Ca(2+) mobilization, we have established a transgenic rice (Oryza sativa) cell line stably expressing apoaequorin, and characterized the interrelationship among MAMP-induced changes in [Ca(2+)](cyt), production of reactive oxygen species (ROS) and protein phosphorylation. Oligosaccharide and sphingolipid MAMPs induced Ca(2+) transients mainly due to plasma membrane Ca(2+) influx, which were dramatically suppressed by a protein phosphatase inhibitor, calyculin A (CA). Hydrogen peroxide and hypo-osmotic shock triggered similar [Ca(2+)](cyt) elevations, which were not affected by CA. MAMP-induced protein phosphorylation, which is promoted by CA, has been shown to be required for ROS production and MAPK activation, while it negatively regulates MAMPs-induced Ca(2+) mobilization and may play a crucial role in temporal regulation of [Ca(2+)](cyt) signature.
Department of Applied Biological Science, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan.
Takamitsu
T
Kurusu
Haruyasu
H
Hamada
Yoshimi
Y
Sugiyama
Toshikazu
T
Yagala
Yasuhiro
Y
Kadota
Takuya
T
Furuichi
Teruyuki
T
Hayashi
Kenji
K
Umemura
Setsuko
S
Komatsu
Akio
A
Miyao
Hirohiko
H
Hirochika
Kazuyuki
K
Kuchitsu
D000331:Aequorin / Q000235:genetics / Q000378:metabolism; D001059:Apoproteins / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D054884:Host-Pathogen Interactions; D007113:Immunity, Innate; D008387:Marine Toxins; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009844:Oligosaccharides / Q000378:metabolism*; D012275:Oryza / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D010080:Oxazoles / Q000494:pharmacology*; D010766:Phosphorylation; D030821:Plants, Genetically Modified / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
D001059:Apoproteins; D008387:Marine Toxins; C520160:N-acetylchitooligosaccharide; D009844:Oligosaccharides; D010080:Oxazoles; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; C060014:apoaequorin; D000331:Aequorin; C059041:calyculin A; D020928:Mitogen-Activated Protein Kinases; D002118:Calcium