Calcium ions, and calcium binding proteins play a role in many cellular processes. Among the proteins bind Ca 2 + ions, with the EF-hand motifs, is distinguished group of proteins called S100 family of proteins. Most S100 proteins have been discovered in the last decade and this family now has 20 proteins. These are proteins with similar primary structure as have 30? 60% amino acid sequence identity. Individual S100 proteins are present in certain cells and tissues, and their function is not fully understood. However, the suggested involvement of S100 proteins in many processes, such as phosphorylation, regulation of enzyme activity, adhesion, neuronal survival and regeneration of nerve cells or apoptosis, indicating that these proteins may play an important role in the cell and intercellular communication.