CXCL12, also known as SDF-1, is a heparin-binding member of the CXC (or alpha-) family of chemokines. SDF-1 alpha and SDF-1 beta are the first cytokines initially identified using the signal sequence trap cloning strategy from a mouse bone-marrow stromal cell line. These proteins were subsequently also cloned from a human stromal cell line. CXCL12β is synthesized as a 93 amino acid (aa) precursor that contains a 21 aa signal sequence and a 72 aa mature region. The mature molecule exhibits a typical three antiparallel beta -strand chemokine-like fold. There are no potential N-linked glycosylation sites. The C-terminus is likely associated with heparin binding. SDF-1 beta circulates and undergoes proteolytic processing. CD26 will remove the first two N-terminal amino acids, possibly creating a reduced-activity chemokine. On the cell surface, the receptor for this chemokine is CXCR4 and syndecan4. Among its many functions, CXCL12 is known to influence lymphopoiesis, regulate patterning and cell number of neural progenitors, and promote angiogenesis. It also enhances the survival of myeloid progenitor cells.

CXCL12, also known as SDF-1, is a small (8 kDa) cytokine highly conserved chemotactic cytokine belonging to the large family of CXC chemokines. SDF-1 alpha and SDF-1 beta are the first cytokines initially identified using the signal sequence trap cloning strategy from a mouse bone-marrow stromal cell line. They are identical except for the four residues present in the C-terminus of SDF1β but absent from SDF1α. CXCL12 binds primarily to CXC receptor 4. The binding of CXCL12 to CXCR4 induces intracellular signaling through several divergent pathways initiating signals related to chemotaxis, cell survival and/or proliferation, increase in intracellular calcium, and gene transcription. The CXCL12/CXCR4 axis is involved in tumor progression, angiogenesis, metastasis, and survival. CXCL12 also can influence lymphopoiesis and regulate patterning and cell number of neural progenitors.