C-X-C motif chemokine ligand 1

The chemokine (C-X-C motif) ligand 1 (CXCL1) is a small peptide belonging to the CXC chemokine family that acts as a chemoattractant for several immune cells, especially neutrophils or other non-hematopoietic cells to the site of injury or infection and plays an important role in regulation of immune and inflammatory responses. It was previously called GRO1 oncogene, GROα, neutrophil-activating protein 3 (NAP-3) and melanoma growth stimulating activity, alpha (MGSA-α). CXCL1 was first cloned from a cDNA library of genes induced by platelet-derived growth factor (PDGF) stimulation of BALB/c-3T3 murine embryonic fibroblasts and named "KC" for its location in the nitrocellulose colony hybridization assay. This designation is sometimes erroneously believed to be an acronym and defined as "keratinocytes-derived chemokine". Rat CXCL1 was first reported when NRK-52E (normal rat kidney-52E) cells were stimulated with interleukin-1β (IL-1β) and lipopolysaccharide (LPS) to generate a cytokine that was chemotactic for rat neutrophils, cytokine-induced neutrophil chemoattractant (CINC). In humans, this protein is encoded by the gene CXCL1 and is located on human chromosome 4 among genes for other CXC chemokines.

== Structure and expression == CXCL1 exists as both monomer and dimer and both forms are able to bind chemokine receptor CXCR2. However, CXCL1 chemokine is able to dimerize only at higher (micromolar) concentrations and its concentrations are only nanomolar or picomolar upon normal conditions, which means that the form of WT CXCL1 is more likely monomeric while dimeric CXCL1 is present only during infection or injury. CXCL1 monomer consists of three antiparallel β-strands followed by C- terminal α-helix and this α-helix together with the first β-strand are involved in forming a dimeric globular structure.