S100 calcium-binding protein P (S100P) is a protein that in humans is encoded by the S100P gene.
The protein encoded by this gene 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. S100 genes include at least 13 members which are located as a cluster on chromosome 1q21; however, this gene is located at 4p16. This protein, in addition to binding Ca<sup>2+</sup>, also binds Zn<sup>2+</sup> and Mg<sup>2+</sup>. This protein may play a role in the etiology of prostate cancer.
S100P has been shown to interact with EZR and RAGE. The interactions between S100P and RAGE are disrupted by cromolyn and pentamidine.