LDL receptor family Arrow/LRP5/LRP6 Arrow/Lrp5/Lrp6 is a subfamily of the LDL receptor (LDLR) family. Arrow, and also its counterparts LRP5 and LRP6 in mammals and in frogs, appears to function as a coreceptor for Wnt together with the seven-transmembrane receptor Frizzled (frz) in forming the Wnt receptor signaling complex.