title: Cloning and characterization of an IKK homologue from pearl oyster, Pinctada fucata.
abstract: IkappaB kinase (IKK) play central roles in cell signaling by regulating nuclear factor-kappaB (NF-kappaB) activation, which is involved in inflammatory response, proliferation, development and bone homeostasis. We report here for the first time that an IKK homologue was cloned and functionally characterized in pearl oyster, Pinctada fucata. The full-length cDNA consists of 2546bp with an ORF encoding a 737 amino acids protein. The putative pearl oyster IKK protein (Pf-IKK) possesses the characteristic organization of the mammalian IKK proteins, namely an amino-terminal kinase domain followed by a leucine zipper region and a carboxylterminal helix-loop-helix motif. Real-time PCR (RT-PCR) analysis indicated that Pf-IKK was ubiquitously expressed in pearl oyster. We also found that lipopolysaccharides (LPS) transiently stimulates IkappaBalpha degradation, but not expression levels of Pf-IKK. When transfected into NIH3T3 cells, Pf-IKK activated the expression of NF-kappaB-controlled reporter gene and induced NF-kappaB translocation, whereas the activation was greatly deduced by pyrrolidine dithiocarbamate (PDTC). We also found that overexpression of Pf-IKK increased the alkaline phosphatase (ALP) activity significantly. Based on the results and the homology to the vertebrate NF-kappaB cascade, these studies help to highlight a potentially important regulatory pathway to the study of the related functions in mollusks.
authors.affiliation: Institute of Marine Biotechnology, Department of Biological Science and Biotechnology, Tsinghua University, Beijing, 100084, China.
authors.forename: Xunhao
authors.initials: X
authors.lastname: Xiong
authors.forename: Qiaoli
authors.initials: Q
authors.lastname: Feng
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Liping
authors.initials: L
authors.lastname: Xie
authors.forename: Rongqing
authors.initials: R
authors.lastname: Zhang
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation; D002478:Cells, Cultured; D003001:Cloning, Molecular; D051550:I-kappa B Kinase / Q000378:metabolism*; D020672:I-kappa B Proteins / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008969:Molecular Sequence Data; D000072000:NF-KappaB Inhibitor alpha; D041681:NIH 3T3 Cells; D010802:Phylogeny; D049911:Pinctada / Q000201:enzymology*; D017434:Protein Structure, Tertiary
chemical_list: D020672:I-kappa B Proteins; D008070:Lipopolysaccharides; C000606205:Nfkbia protein, mouse; D000072000:NF-KappaB Inhibitor alpha; D051550:I-kappa B Kinase; D000469:Alkaline Phosphatase