S100 calcium-binding protein A10 (S100A10), a member of the S100 family of proteins containing two EF-hand calcium-binding motifs, is also known as protein S100-A10, calpactin I light chain, cellular ligand of annexin II, p10 protein and p11, which can be found as a free monomer, a homodimer, or a heterotetramer composed of a p11 dimer complex with two molecules of annexin II. S100A10 is an integral part of cellular structural scaffolding that interacts with plasma membrane proteins through its association with annexin II. S100A10 also works together with cytosolic and peripheral membrane-associated proteins such as AHNAK in the development of the intracellular membrane. Furthermore,S100A10 has been implicated in the transportation of proteins involved in mood regulation, nociception, and cell polarization. Complexed with the annexin II, S100A10 binds receptor and channel proteins and guides them to the cell surface, resulting in increased membrane localization and consequent magnified functional expression of these proteins.