CD93(ClusterofDifferentiation93)isaproteinthatinhumansisencodedbytheCD93gene.CD93belongstotheGroupXIVC-Typelectinfamilyandismappedto20p11.21.Theproteinencodedbythisgeneisacell-surfaceglycoproteinandtypeImembraneproteinthatwasoriginallyidentifiedasamyeloidcell-specificMarker.TheencodedproteinwasoncethoughttobeareceptorforC1q,butnowisthoughttoinsteadbeinvolvedinintercellularadhesionandintheclearanceofapoptoticcells.Theintracellularcytoplasmictailofthisproteinhasbeenfoundtointeractwithmoesin,aproteinknowntoplayaroleinlinkingtransmembraneproteinstothecytoskeletonandintheremodellingofthecytoskeleton.Ithasalsoshowedthatthisreceptorisapositivemarkerforallbonemarrow-repopulatingstemcellsbecauseitisexpressedonbothCD34-negativeandCD34-positivestemcellsfromumbilicalcordbloodandadultbonemarrow.Inaddition,highlypurifiedlineage-negativecellswiththeCD93proteinnotonlyhavebonemarrow-repopulatingcapacitybutalsocandifferentiateintohumanhepatocytesinvivo.