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

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

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

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.

See also

• S100 protein family
• Biomarker
• Neurodegenerative diseases