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SDF-1α, also known as CXCL12, is a chemokine protein that plays a critical role in immune cell trafficking, hematopoiesis, and tissue repair. It is produced by stromal cells, endothelial cells, and other cell types in response to various stimuli, including inflammation and tissue injury. SDF-1α/CXCL12 exerts its biological effects by binding to its receptor CXCR4, a G protein-coupled receptor expressed on the surface of immune cells, hematopoietic stem cells, and other cell types.
The protein structure of SDF-1α/CXCL12 consists of a conserved N-terminal region and a flexible loop region, which is important for receptor binding and activation of downstream signaling pathways. The interaction between SDF-1α/CXCL12 and CXCR4 regulates the migration, homing, and retention of immune cells in specific tissues, as well as the mobilization and homing of hematopoietic stem cells.