Grouper (Epinephelus coioides) MyD88 and Tollip: Intracellular localization and signal transduction function

• Published in: Fish & shellfish immunology Vol. 42; no. 1; pp. 153 - 158
• Main Authors: Li, Yan-Wei, Wang, Zheng, Mo, Ze-Quan, Li, Xia, Luo, Xiao-Chun, Dan, Xue-Ming, Li, An-Xing
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2015
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Cloning, Molecular; Cluster Analysis; Cytoplasm - metabolism; DNA Primers - genetics; DNA, Complementary - genetics; Epinephelus coioides; HEK293 Cells; Humans; Intracellular localization; Intracellular Signaling Peptides and Proteins - genetics; Intracellular Signaling Peptides and Proteins - metabolism; Luciferase reporter assay; Luciferases; Marine; Molecular Sequence Data; MyD88; Myeloid Differentiation Factor 88 - genetics; Myeloid Differentiation Factor 88 - metabolism; NF-kappa B - metabolism; Open Reading Frames; Perciformes - metabolism; Perciformes - physiology; Phylogeny; Sequence Analysis, DNA; Signal Transduction - physiology; Tollip; Epinephelus coioides; Luciferase reporter assay; Intracellular localization; MyD88; Tollip
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2014.10.041

Myeloid differentiation factor 88 (MyD88) and Toll-interacting protein (Tollip) are two important regulatory proteins of the Toll-like receptor (TLR) signaling pathways. In this paper, a Tollip sequence of grouper (Epinephelus coioides) was identified and the signal transduction functions of Tollip and MyD88 were studied. The full length of E. coioides Tollip (EcTollip) cDNA with an open reading frame (ORF) of 1734 nucleotides encoded a putative protein of 274 amino acid residues. The EcTollip protein had conservative domains with mammalian homologous proteins, and high identity (78%–95%) with other vertebrates. MyD88 and Tollip were distributed in the HeLa cytoplasm in a highly condensed form. Over-expression of MyD88 could activate nuclear factor-κB (NF-κB) and its function was dependent on the death domain and ID domain on the N-terminal. Some important functional sites of mammalian MyD88 also affected fish MyD88 signal transduction. Tollip impaired NF-κB signals activated by MyD88, and its activity was dependent on the coupling of ubiquitin to the endoplasmic reticulum degradation (CUE) domain on the C-terminal. These results suggest that MyD88 and Tollip of fish and mammals are conservative on function during evolution. •A Tollip sequence of Epinephelus coioides was identified with a very conservative structure.•Both MyD88 and Tollip were localized in the cytoplasm in a highly condensed form.•Tollip-impaired MyD88-activated NF-κB signaling depended on its C-terminal CUE domain.