Cytokine that binds to and signals through the IL1RL2/IL-36R receptor which in turn activates NF-kappa-B and MAPK signaling pathways in target cells linked to a pro-inflammatory response. Part of the IL-36 signaling system that is thought to be present in epithelial barriers and to take part in local inflammatory response; similar to the IL-1 system with which it shares the coreceptor IL1RAP. Stimulates production of interleukin-6 and interleukin-8 in synovial fibrobasts, articular chondrocytes and mature adipocytes. Induces expression of a number of antimicrobial peptides including beta-defensins 4 and 103 as well as a number of matrix metalloproteases. Seems to be involved in skin inflammatory response by acting on keratinocytes, dendritic cells and indirectly on T-cells to drive tissue infiltration, cell maturation and cell proliferation. In cultured keratinocytes induces the expression of macrophage, T-cell, and neutrophil chemokines, such as CCL3, CCL4, CCL5, CCL2, CCL17, CCL22, CL20, CCL5, CCL2, CCL17, CCL22, CXCL8, CCL20 and CXCL1, and the production of pro-inflammatory cytokines such as TNF-alpha, IL-8 and IL-6. Interacts with cargo receptor TMED10; the interaction mediates the translocation from the cytoplasm into the ERGIC (endoplasmic reticulum-Golgi intermediate compartment) and thereby secretion. The secretion is dependent on protein unfolding and facilitated by the cargo receptor TMED10; it results in protein translocation from the cytoplasm into the ERGIC (endoplasmic reticulum-Golgi intermediate compartment) followed by vesicle entry and secretion. Expression at low levels in tonsil, bone marrow, heart, placenta, lung, testis and colon but not in any hematopoietic cell lines. Not detected in adipose tissue. Expressed at higher levels in psoriatic plaques than in symptomless psoriatic skin or healthy control skin. Increased levels are not detected in inflamed joint tissue. By pro-inflammatory cytokines IL1A, IL1B and TNF in synovial fibroblasts. By IL1A and TNF in keratinocytes. Constitutive in articular chondrocytes. N-terminal truncation leads to a dramatic enhancement of its activity (>1000-fold). Belongs to the IL-1 family. Interleukin-1 entry