S100P gene contains two exons and one intron. Genomic size of 3,332 bases.

1279 bases mRNA; 288 bases coding sequences. The transcript is on Chromosome 4 at location 6,745,697-6,749,797.

None identified.

S100P protein consists of 95 amino acids with a molecular weight of 10.4 kDa.
S100P is a Ca²⁺ binding protein that belongs to S100 family ("Soluble in 100% saturated solution with ammonium sulfate") which was first isolated from human placenta and is therefore designated as "P". S100 family includes at least 26 members, which are thought to be expressed only in vertebrates and are present in a tissue and cell-specific manner. S100 proteins are characterized by common structural motifs including 2 EF-hands (helix-loop-helix calcium binding domains) with different affinities for calcium ions, a central hinge region and the C-terminal extension. The N-terminal half of the protein contains an unconventional EF hand that binds calcium with lower affinity, while the C-terminal is canonical and binds calcium with high affinity. The connecting hinge region and the C-terminal extension are the most variable regions and thus determine the functional specificity of S100 family members, including S100P. In addition to Ca²⁺, S100P also binds Zn²⁺ and Mg²⁺ and can form homo- and heterodimers.

S100P is expressed in various normal tissues including placenta, lung, heart, kidney, bladder, skeletal muscle, bone marrow, spleen, mammary epithelium, epidermis, prostate gland, gastric and intestinal mucosa, and malignant tissues such as pancreatic ductal adenocarcinoma, pancreatic intraductal papillary mucinous neoplasm, non-small-cell lung cancer, melanoma, gastric adenocarcinoma, ovarian, breast, colon and prostate carcinoma as well as in the body fluids such as tear, pancreatic juice, blood and urine.

Cytoplasm, nucleus, also secreted in the culture media.

S100P is involved in diverse biological functions but the exact role or mechanism of its action is still largely unknown. Upon binding of calcium ions S100P undergoes a conformational change that results in an exposure of a hydrophobic surface which allows the interaction with specific target proteins. To date, several S100P interacting partners have been identified including S100P binding protein S100PBP, EZR, S100A1, ECD, CacyBP, RAGE, S100Z and S100A6, but the consequences of their interactions are not fully understood.

S100P shares 50% sequence identity with human S100A1 and 44% identity with S100B.

Mutations have not been reported.