Identification of critical regions within the TIR domain of IL-1 receptor type I. (November 2015)

• Record Type: Journal Article
• Authors: Radons, Jürgen; Falk, Werner; Dove, Stefan
• Is Part Of: International journal of biochemistry & cell biology. Volume 68(2015:Nov.)
• Page Start: 15
• Page End: 20
• Publication Date: 2015-11
• Subjects: IL-1 -- IL-1RI -- TIR domain -- NF-κB -- Site-directed mutagenesis -- Homology modeling; DEAE diethylaminoethyl -- FACS fluorescence-activated cell sorting -- FCS fetal calf serum -- IL interleukin -- IL-1RI IL-1 receptor type I -- IL-1RAcP IL-1 receptor accessory protein -- IL-1RAPL IL-1RAcP-like -- LPS lipopolysaccharide -- Mal MyD88 adaptor-like protein -- MyD88 myeloid differentiation primary response protein MyD88 -- NF-κB nuclear factor kappa B -- PI3K phosphatidylinositol 3-kinase -- PBS phosphate-buffered saline -- PKB protein kinase B -- SI stimulation index -- TBS Tris-buffered saline -- TILRR Toll-like and IL-1R regulator -- TIR Toll/IL-1 receptor -- TLR Toll-like receptor -- WT wild type.; Biochemistry -- Periodicals; Cytology -- Periodicals; Biochemistry -- Periodicals; Cell Biology -- Periodicals; Biochimie -- Périodiques; Cytologie -- Périodiques; Biochimie; Cytologie; Biochemistry; Cytology; Ressource Internet (Descripteur de forme); Périodique électronique (Descripteur de forme); Periodicals; 572.05
• DOI: 10.1016/j.biocel.2015.08.009
• Languages: English
• ISSNs: 1357-2725

Abstract

Highlights: We generated a homology model of the mouse IL-1RI TIR domain. We found putative TIR-TIR domain interfaces for heterotypic interactions. Helix αC′ of mouse IL-1RI is essential for IL-1 signaling. The region around αC′ may interact with box 3 of IL-1RAcP or MyD88. The acidic C-terminus of the BB-loop is not necessary for function. Abstract: Interleukin-1 receptor type I (IL-1RI) belongs to a superfamily of proteins characterized by an intracellular Toll/IL-1 receptor (TIR) domain. This domain harbors three conserved regions called boxes 1-3 that play crucial roles in mediating IL-1 responses. Boxes 1 and 2 are considered to be involved in binding of adapter molecules. Amino acids possibly crucial for IL-1RI signaling were predicted via homology models of the IL-1RI TIR domain based on the crystal structure of IL-1RAPL. The role of ten of these residues was investigated by site-directed mutagenesis and a functional luciferase assay reflecting NF-κB activity in transiently transfected Jurkat cells. In particular, the mutants E437K/D438K, E472A/E473A and S465A/S470A/S471A/E472A/E473A showed decreased and the mutant E437A/D438A increased IL-1 responsiveness compared to the mouse IL-1RI wild type. In conclusion, the αC′ helix (Q469-E473 in mouse IL-1RI) is probably involved in heterotypic interactions of IL-1RI with IL-1RAcP or MyD88.