IL1RAP

Interleukin 1 induces synthesis of acute phase and proinflammatory proteins during infection, tissue damage, or stress, by forming a complex at the cell membrane with an interleukin 1 receptor and an accessory protein. This gene encodes the interleukin 1 receptor accessory protein. The protein is a necessary part of the interleukin 1 receptor complex which initiates signalling events that result in the activation of interleukin 1-responsive genes. Alternative splicing of this gene results in two transcript variants encoding two different isoforms, one membrane-bound and one soluble. The ratio of soluble to membrane-bound forms increases during acute-phase induction or stress. [provided by RefSeq, Nov 2009]

Full Name

Interleukin 1 Receptor Accessory Protein

Function

Coreceptor for IL1RL2 in the IL-36 signaling system (By similarity).

Coreceptor with IL1R1 in the IL-1 signaling system. Associates with IL1R1 bound to IL1B to form the high affinity interleukin-1 receptor complex which mediates interleukin-1-dependent activation of NF-kappa-B and other pathways. Signaling involves the recruitment of adapter molecules such as TOLLIP, MYD88, and IRAK1 or IRAK2 via the respective TIR domains of the receptor/coreceptor subunits. Recruits TOLLIP to the signaling complex. Does not bind to interleukin-1 alone; binding of IL1RN to IL1R1, prevents its association with IL1R1 to form a signaling complex. The cellular response is modulated through a non-signaling association with the membrane IL1R2 decoy receptor. Coreceptor for IL1RL1 in the IL-33 signaling system. Can bidirectionally induce pre- and postsynaptic differentiation of neurons by trans-synaptically binding to PTPRD (By similarity).

May play a role in IL1B-mediated costimulation of IFNG production from T-helper 1 (Th1) cells (Probable).

Isoform 2:
Associates with secreted ligand-bound IL1R2 and increases the affinity of secreted IL1R2 for IL1B; this complex formation may be the dominant mechanism for neutralization of IL1B by secreted/soluble receptors (PubMed:12530978).

Enhances the ability of secreted IL1R1 to inhibit IL-33 signaling (By similarity).

Isoform 4:
Unable to mediate canonical IL-1 signaling (PubMed:19481478).

Required for Src phosphorylation by IL1B. May be involved in IL1B-potentiated NMDA-induced calcium influx in neurons (By similarity).

Biological Process

Immune response Source: ProtInc
Inflammatory response Source: ProtInc
Innate immune response Source: UniProtKB-KW
Positive regulation of interleukin-13 production Source: Ensembl
Positive regulation of interleukin-4 production Source: Ensembl
Positive regulation of interleukin-5 production Source: Ensembl
Positive regulation of interleukin-6 production Source: Ensembl
Positive regulation of NF-kappaB transcription factor activity Source: GO_Central
Positive regulation of synapse assembly Source: UniProtKB
Protein-containing complex assembly Source: ProtInc
Regulation of postsynaptic density assembly Source: Ensembl
Regulation of presynapse assembly Source: Ensembl
Synaptic membrane adhesion Source: Ensembl
Trans-synaptic signaling by trans-synaptic complex Source: Ensembl

Cellular Location

Isoform 1: Cell membrane
Isoform 2&3: Secreted

Topology

Extracellular: 21-367
Helical: 368-388
Cytoplasmic: 389-570