Functions as an agonist of NF-kappa B activation through the orphan IL-1-receptor-related protein 2/IL1RL2. 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 (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. May play a role in pro-inflammatory responses during particular neutrophilic airway inflammation. May be involved in the innate immune response to fungal pathogens. 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. 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 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. 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. N-terminal truncation leads to a dramatic enhancement of its activity (>1000-fold) (PubMed:21965679). Proteolytically cleaved by cathepsin CTSG (By similarity). Belongs to the IL-1 family.