S100A2 (also S100L and CaN19) is a 10 kDa member of the S100 family, EF-hand superfamily of Ca-binding proteins. It is expressed by multiple cell types including keratinocytes, chondrocytes, and bronchial epithelium. S100A2 regulates both Ca2+ and Zn2+ (in human) within cells and increases p53 activity. S100A2 forms both noncovalent and covalent homodimers and a homotetramer under certain conditions. Human S100A2 is 98 amino acids (aa) in length. It contains two EF-hand motifs (aa 13 - 48 and 51 - 86) plus a calcium (aa 64 - 75) and Zn2+ (aa 17 - 22) binding site. There is one potential alternative splice form that shows a 40 aa insertion after Gly48. Full-length human S100A2 shares 89% and 85% aa identity with bovine and canine S100A2, respectively.