Stromal Cell-Derived Factor-1 alpha (SDF-1 alpha)
Stromal cell-derived factor-1 (SDF-1; CXCL12) has two forms, SDF-1 alpha and SDF-1 beta. They are encoded by a single gene and arise by alternative splicing. The two proteins are identical except for the additional four amino acids present in the carboxy-terminus of SDF-1 beta. SDF-1 is a chemoattractant for T-lymphocytes and monocytes, but not neutrophils. SDF-1 is a ligand for the CXCR4 receptor that functions as a co-receptor for lymphocytetropic HIV-1 strains and plays a role in the inhibition of infection in HIV.
Swiss-Prot Accession Number: P48061-2