CXCR4(redirected from lipopolysaccharide-associated protein 3)
CXCR4A gene on chromosome 2q21 that encodes a seven-transmembrane G protein-coupled receptor belonging to the CXC chemokine receptor family, which binds specifically to stromal cell-derived factor-1, transducing a signal by increasing intracellular calcium ions and enhancing MAPK1/MAPK3 activation. It acts as a receptor for extracellular ubiquitin, is involved in haematopoiesis and in cardiac ventricular septum formation, plays a role in gastrointestinal tract vascularisation by regulating vascular branching and/or remodelling in endothelial cells, may be involved in cerebellar development and, in the CNS, may mediate hippocampal-neuron survival.
CXCR4 acts with the CD4 to support HIV entry into cells; it is highly expressed in breast cancer cells. CXCR4 mutations cause WHIM (warts, hypogammaglobulinaemia, infections, and myelokathexis) syndrome.