CXCR4 (C-X-C chemokine receptor type 4) is a member of the G-protein coupled receptor (GPCR1) family. It is expressed as a multipass membrane protein in several tissues where it acts as the receptor for the C-X-C chemokine CXCL12/SDF-1. This ligand increases intracellular calcium ion levels and enhances activation of the MAPK1/MAPK3 cascade.
