S100A12 is a member of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100 proteins are localized in the cytoplasm and/or nucleus of a wide range of cells, and involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. S100A12 is proposed to be involved in specific calcium-dependent signal transduction pathways and its regulatory effect on cytoskeletal components may modulate various neutrophil activities. S100A12 is also a ligand for RAGE. Interaction with RAGE on mononuclear phagocytes, lymphocytes and endothelium triggers cellular activation. Nuclear factor kappa B--a key transcription factor for inflammatory events--is activated by S100A12/RAGE. S100A12 has also been shown to have anti-microbial properties.