http://www.creativebiomart.net/description_382801_12.htm

Stromal cell-derived factor 1, also known as C-X-C motif chemokine 12, Intercrine reduced in hepatomas, Pre-B cell growth-stimulating factor, SDF-1, PBSF, CXCL12 and SDF1, is a secreted protein which belongs to the intercrine alpha (chemokine CxC) family. CXCL12 / SDF-1 is widely expressed in various organs including heart, liver, brain, kidney, skeletal muscle, and lymphoid organs, and is highly conserved between species. CXCL12 / SDF-1 is expressed in two isoforms from a single gene that encodes two splice variants, SDF1 alpha; and SDF1 beta, which are identical except for the four residues present in the C-terminus of SDF1 beta; but absent from SDF1 alpha;. As a highly efficacious lymphocyte chemoattractant, CXCL12 / SDF-1 activates and directs the migration of leukocytes in response to proinflammatory stimuli such as LPS, TNF, or interleukins. It has been demonstrated that CXCL12 / SDF-1 promotes tumor growth and malignancy, enhances tumor angiogenesis, participates in tumor metastasis, and thus plays an important role in carcinoma pathogenesis. In addition, CXCL12 / SDF-1 is identified as the biological ligand for CXC-chemokine receptor 4 (CXCR4), which is widely expressed in leukocytes and acts as the cofactor for HIV-1 entry, and inhibits the HIV-1 infection. Furthermore, SDF1 is rapidly inactivated via N-terminal processing by cathepsin G associated with the membrane of B-cells, NK cells and to a lesser extent, T-cells.