CD90

CD90

CD90, also known as Thy-1, is a glycoprotein that is expressed on the surface of various cell types, including stem cells, neurons, and fibroblasts. It is a member of the immunoglobulin superfamily and plays a crucial role in cell-cell and cell-matrix interactions. CD90 is involved in a variety of biological processes, including cell adhesion, cell migration, and signal transduction.

Structure

CD90 is a small glycoprotein with a molecular weight of approximately 25-37 kDa, depending on the extent of glycosylation. It consists of a single V-like immunoglobulin domain, a short stalk region, a transmembrane domain, and a cytoplasmic tail. The extracellular domain is responsible for its interactions with other molecules, while the cytoplasmic tail is involved in intracellular signaling pathways.

Expression

CD90 is widely expressed in the body, with notable expression in:

• Hematopoietic stem cells
• Mesenchymal stem cells
• Neurons
• Fibroblasts
• Endothelial cells

The expression of CD90 can vary depending on the cell type and the physiological or pathological state of the tissue.

Function

CD90 is involved in several key functions:

• Cell Adhesion: CD90 mediates cell-cell and cell-matrix adhesion, which is essential for tissue architecture and integrity.
• Signal Transduction: It participates in signaling pathways that regulate cell proliferation, differentiation, and survival.
• Immune Response: CD90 is involved in modulating immune responses, particularly in the context of T cell activation and inflammation.
• Stem Cell Biology: It is a marker for identifying and isolating stem cells, particularly mesenchymal stem cells, due to its role in maintaining stem cell properties.

Clinical Significance

CD90 has been studied in various clinical contexts:

• Cancer: Altered expression of CD90 has been observed in several types of cancer, including liver cancer and glioma. It is thought to play a role in tumor progression and metastasis.
• Regenerative Medicine: Due to its expression on stem cells, CD90 is a target for regenerative therapies aimed at repairing damaged tissues.
• Fibrosis: CD90 is implicated in fibrotic diseases, where it may contribute to the excessive deposition of extracellular matrix components.

Also see

• CD44
• CD34
• Stem cell markers
• Immunoglobulin superfamily