S-100 protein beta chain (S100B),a member of the S-100 family, is also known as S-100 protein subunit beta and S100 calcium-binding protein B, which contains two EF-hand domains. S100B can weakly bind calcium but bind zinc very tightly-distinct binding sites with different affinities exist for both ions on each monomer. Also, S100B can bind to and initiate the activation of STK38 by releasing autoinhibitory intramolecular interactions within the kinase. Interaction with AGER after myocardial infarction,S100B may play a role in myocyte apoptosis by activating ERK1/2 and p53/TP53 signaling. Fuethermore,S100B could assist ATAD3A cytoplasmic processing, preventing aggregation and favoring mitochondrial localization. S100B may mediate calcium-dependent regulation on many physiological processes by interacting with other proteins, such as TPR-containing proteins, and modulating their activity.