Interleukin-1 Receptor Type 1 Is a Substrate for γ-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 presenilindependent ␥-secretase activity. A metalloprotease-dependent proteolytic event liberates soluble IL-1R1 ectodomain and produces an ϳ32-kDa C-terminal domain. This IL-1R1 C-terminal domain is a substrate for subsequent ␥-secretase cleavage, which generates an ϳ26-kDa intracellular domain. Specific pharmacological ␥-secretase inhibitors, expression of dominant negative presenilin-1, or presenilin deficiency independently inhibit generation of the IL-1R1 intracellular domain. Attenuation of ␥-secretase activity also impairs responsiveness to IL-1␤-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 ␥-secretase cleavage. These findings also suggest that regulated intramembrane proteolysis may be a control mechanism for IL-1R1-mediated signaling.

γ-Secretase Activity Is Required for Regulated Intramembrane Proteolysis of Tumor Necrosis Factor (TNF) Receptor 1 and TNF-mediated Pro-apoptotic Signaling

“…Through genetic knock-out of the presenilins, we have further demonstrated the essential role of the presenilins in ␥-secretase cleavage of TNFR1. Although it has been shown that ␥-secretase cleavage of the insulin-like growth factor 1 receptor, Notch, IL-1 receptor I, p75 NTR , or ErbB-4 receptor occurs in the presence of their corresponding ligands (40,50,58,(77)(78)(79), ligand-induced cleavage has not been shown for other receptors, such as the growth hormone receptor. Here we demonstrate that TNF␣ stimulation can induce ectodomain shedding, generation of TNFR1 CTF, and subsequent ␥-secretase cleavage of TNFR1, perhaps pointing to a general mechanism of ligand-mediated regulated intramembrane proteolysis.…”

“…Plasmids, Site-directed Mutagenesis, and TransfectionspcDNA3.1-PS1 was generated in-house as described previously (40). The pBABE-TNFR1 (human) expression plasmid was a gift from Dr. Martin S. Kluger (Yale University School of Medicine).…”

“…The pcDNA3.1-HA-RIPK1 and pcDNA3-Myc-TRADD was obtained from Tularick Inc. Transient transfections of HEK293T were performed using the calcium phosphate precipitation method as described previously (40).…”

“…The majority of known ␥-secretase substrates also undergo ectodomain shedding in the extracellular domain as a prerequisite for ␥-secretase-mediated cleavage of the remaining membrane-bound CTF. The identification of members of the IL-1/Toll-like receptor superfamily, including IL-1 receptor I, IL-1 receptor II, and IL-6 receptor, as substrates for ␥-secretase-dependent regulated intramembrane proteolysis (40,52,53) prompted us to examine whether TNFR1 undergoes ectodomain shedding and subsequent cleavage by ␥-secretase.…”

An Interactive Network of Elastase, Secretases, and PAR-2 Protein Regulates CXCR1 Receptor Surface Expression on Neutrophils

“…The combined mode of action of ␣-and ␥-secretases is reminiscent of the sequential protease involvement in processing of substrates of the ␥-secretase, such as the amyloid precursor protein (29,30). Besides amyloid precursor protein, secretases have been reported to play a role in cleaving and processing a variety of different proteins, including MHC class I proteins, in particular human leukocyte antigen A2 (31), the interleukin-1 receptor type 1 (IL-1R1) (32), leukosialin/ CD43 (33), transmembrane-associated chemokines, the Notch receptor, and others (34). These processes probably occur close to the cellular membrane through juxtamembranous cleavage events as demonstrated previously for CD43 (33).…”