title: The modulation of haemolymph arginine kinase on the extracellular ATP induced bactericidal immune responses in the Pacific oyster Crassostrea gigas.
abstract: Arginine kinase is an important phosphagen kinase (PK) which plays an essential role in ATP buffering systems in invertebrates. In the present study, an arginine kinase (designated CgAK) was isolated by the lipopolysaccharide (LPS) affinity chromatography from the haemolymph of Crassostrea gigas. CgAK could directly bind to LPS in a concentration-dependent manner with the dissociation constant (Kd) of 2.46 × 10(-6) M. The interaction with LPS significantly decreased the ATP hydrolytic activity of CgAK, which in turn lead to the accumulation of ATP in vitro. The extracellular ATP stimulation could induce Ca(2+) influx, reactive oxygen species (ROS) production, and the release of lysosomal enzyme in the cellular immune response. In addition, ATP stimulation provoked the bactericidal activity towards Escherichia coli, and the scavenging ROS with N-acetyl-l-cysteine (NAC) abrogated the bactericidal activity, indicating that ATP stimulation could induce ROS-dependent antimicrobial activity in haemocytes. Collectively, the results demonstrated that the haemolymph CgAK could serve as an important purinergic regulator to modulate extracellular ATP, which might further have an important effect on the purinergic signaling-activated innate immune response of oyster.
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Jia
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian 116023, China. Electronic address: lshsong@dlou.edu.cn.
authors.forename: Linsheng
authors.initials: L
authors.lastname: Song
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001122:Arginine Kinase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D049896:Crassostrea / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D004926:Escherichia coli / Q000502:physiology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006458:Hemolymph / Q000276:immunology / Q000382:microbiology; D007113:Immunity, Innate; D008957:Models, Genetic; D016366:Open Reading Frames; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D029941:Fish Proteins; D000255:Adenosine Triphosphate; D001122:Arginine Kinase
keywords: Arginine kinase; Crassostrea gigas; Extracellular ATP; Lipopolysaccharide; Reactive oxygen species