CX3CR1fractalkine

CX3CR1, also known as the fractalkine receptor, is a G protein-coupled receptor primarily expressed on immune cells. It is the sole receptor for the chemokine fractalkine (CX3CL1), also known as fractalkine. Fractalkine is unique among chemokines as it exists in both soluble and membrane-bound forms. This dual nature allows it to mediate cell-to-cell adhesion and migration.

The CX3CR1 receptor plays a significant role in the immune system, particularly in the recruitment and regulation of various immune cells. It is expressed on monocytes, macrophages, natural killer (NK) cells, T cells, and dendritic cells. Upon binding to fractalkine, CX3CR1 triggers intracellular signaling pathways that influence cell adhesion, migration, survival, and activation.

In inflammatory conditions, CX3CR1-fractalkine interactions contribute to the recruitment of immune cells to sites of inflammation. For instance, it is implicated in the pathogenesis of atherosclerosis, where it promotes the adhesion and transmigration of monocytes and macrophages into the arterial wall. Furthermore, CX3CR1 signaling is involved in neuroinflammation, influencing the behavior of microglia and astrocytes in the central nervous system. Research has also highlighted its role in cancer immunity, impacting tumor-associated macrophages and T cell infiltration. The specific functions of CX3CR1 can vary depending on the cell type and the context of the immune response.