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-defensin 4 and beta-defensin 103 as well as a number of matrix metalloproteases (By similarity). 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. Induces the production of pro-inflammatory cytokines in bone marrow-derived dendritic cells (BMDCs), including IL-12, Il-1 beta, IL-6, TNF-alpha and IL-23, and activates p38 MAPK phosphorylation in BMDCs. Involved in dendritic cell maturation by stimulating the surface expression of CD80, CD86 and MHC class II. Induces the production of IFN-gamma, IL-4 and IL-17 by T-helper 1 (Th1) cells, cultured CD4(+) T-cells and splenocytes. Interacts with cargo receptor TMED10; the interaction mediates the translocation from the cytoplasm into the ERGIC (endoplasmic reticulum-Golgi intermediate compartment) and thereby secretion. Secreted upon LPS treatment followed by ATP-induced activation of P2rx7. 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 (By similarity). N-terminal truncation leads to a dramatic enhancement of its activity (>1000-fold). Belongs to the IL-1 family. Truncated N-terminus.