Members of the chemokine family of proinflammatory mediators interact with target cells by binding to members of the seven transmembrane spanning family of G protein-coupled receptors. We have been interested in identifying chemokine receptors involved in the regulation of hematopoietic stem cell proliferation and during these studies have cloned a
novel chemokine receptor which is called D6. D6 is a  chemokine-specific receptor but is highly promiscuous within this context and binds most members of this subfamily. Curiously, it does not seem to signal in the way that other chemokine receptors do and thus it has not yet been given a systematic name. D6 is expressed in the placenta and in the lung and liver but is detectable at low levels in most other tissues. Unlike many other chemokine receptors, it is not highly expressed in hematopoietic cells and thus its major domain of function may not be in this system.