title: Interleukin-1 receptor type 1 is a substrate for gamma-secretase-dependent regulated intramembrane proteolysis.
abstract: Biochemical and genetic studies have revealed that the presenilins interact with several proteins and are involved in the regulated intramembrane proteolysis of numerous type 1 membrane proteins, thereby linking presenilins to a range of cellular processes. In this study, we report the characterization of a highly conserved tumor necrosis factor receptor-associated factor-6 (TRAF6) consensus-binding site within the hydrophilic loop domain of presenilin-1 (PS-1). In coimmunoprecipitation studies we indicate that presenilin-1 interacts with TRAF6 and interleukin-1 receptor-associated kinase 2. Substitution of presenilin-1 residues Pro-374 and Glu-376 by site-directed mutagenesis greatly reduces the ability of PS1 to associate with TRAF6. By studying these interactions, we also demonstrate that the interleukin-1 receptor type 1 (IL-1R1) undergoes intramembrane proteolytic processing, mediated by presenilin-dependent gamma-secretase activity. A metalloprotease-dependent proteolytic event liberates soluble IL-1R1 ectodomain and produces an approximately 32-kDa C-terminal domain. This IL-1R1 C-terminal domain is a substrate for subsequent gamma-secretase cleavage, which generates an approximately 26-kDa intracellular domain. Specific pharmacological gamma-secretase inhibitors, expression of dominant negative presenilin-1, or presenilin deficiency independently inhibit generation of the IL-1R1 intracellular domain. Attenuation of gamma-secretase activity also impairs responsiveness to IL-1beta-stimulated activation of the MAPKs and cytokine secretion. Thus, TRAF6 and interleukin receptor-associated kinase 2 are novel binding partners for PS1, and IL-1R1 is a new substrate for presenilin-dependent gamma-secretase cleavage. These findings also suggest that regulated intramembrane proteolysis may be a control mechanism for IL-1R1-mediated signaling.
authors.affiliation: Signal Transduction Laboratory, Biochemistry Department, University College Cork, Cork, Ireland.
authors.forename: Baukje M
authors.initials: BM
authors.lastname: Elzinga
authors.forename: Ciara
authors.initials: C
authors.lastname: Twomey
authors.forename: James C
authors.initials: JC
authors.lastname: Powell
authors.forename: Frances
authors.initials: F
authors.lastname: Harte
authors.forename: Justin V
authors.initials: JV
authors.lastname: McCarthy
mesh_terms: D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D006801:Humans; D053592:Interleukin-1 Receptor-Associated Kinases / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D053764:Presenilin-1 / Q000235:genetics / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D017433:Protein Structure, Secondary / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D051381:Rats; D053573:Receptors, Interleukin-1 Type I / Q000235:genetics / Q000378:metabolism*; D048029:TNF Receptor-Associated Factor 6 / Q000235:genetics / Q000378:metabolism*
chemical_list: D016207:Cytokines; C508590:IL1R1 protein, human; D053764:Presenilin-1; D011480:Protease Inhibitors; D053573:Receptors, Interleukin-1 Type I; D048029:TNF Receptor-Associated Factor 6; D053592:Interleukin-1 Receptor-Associated Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D053829:Amyloid Precursor Protein Secretases