Syndecan1

Syndecan1, also known as CD138, is a transmembrane proteoglycan that plays a crucial role in cell surface adhesion, cell signaling, and extracellular matrix organization. It is a member of the syndecan family, which are type I transmembrane proteins characterized by an extracellular domain heavily substituted with glycosaminoglycan chains. Syndecan1 is encoded by the SDC1 gene.

This protein is widely expressed in epithelial and endothelial cells, and its expression levels can vary significantly during development and in disease states. During embryonic development, syndecan1 is involved in processes such as cell proliferation, migration, and differentiation. In adult tissues, it contributes to maintaining tissue structure and integrity.

Syndecan1 acts as a co-receptor for various growth factors and cytokines, binding them to the cell surface and modulating their signaling pathways. This interaction is important for regulating cell growth, survival, and inflammatory responses. The heparan sulfate chains attached to syndecan1 are key mediators of these interactions, as they can bind to a diverse range of extracellular molecules.

In the context of disease, syndecan1 is often dysregulated. It is notably overexpressed in many types of cancer, where it can promote tumor growth, invasion, and metastasis by interacting with signaling molecules involved in these processes. Conversely, reduced syndecan1 expression can be observed in certain conditions, suggesting complex and context-dependent roles. Its presence on plasma cells also makes it a valuable diagnostic marker for multiple myeloma.