S100B

S100B is a protein that in humans is encoded by the S100B gene. It is a member of the S100 protein family, which is composed of 21 different members that exhibit a high degree of sequence similarity. S100B is located in the cytoplasm and/or nucleus of a wide range of cells. It is involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation.

Structure[edit | edit source]

S100B is a small, acidic protein with a molecular weight of approximately 10.5 kDa. It is composed of two EF-hand motifs, each of which can bind a calcium ion. The binding of calcium induces a conformational change in the protein, which allows it to interact with its target proteins.

Function[edit | edit source]

S100B has both intracellular and extracellular functions. Intracellularly, it interacts with a variety of proteins to modulate cellular processes such as protein phosphorylation, cytoskeletal dynamics, and cell growth and differentiation. Extracellularly, S100B acts as a neurotrophic factor and can stimulate neurite outgrowth.

Clinical significance[edit | edit source]

Elevated levels of S100B in the blood are associated with certain pathological conditions, including brain injury, neurodegenerative diseases, and certain types of cancer. As such, S100B is often used as a biomarker for these conditions.