Chaperone specifically assisting the folding of beta- propeller/EGF modules within the family of low-density lipoprotein receptors (LDLRs). Acts as a modulator of the Wnt pathway through chaperoning the coreceptors of the canonical Wnt pathway, LRP5 and LRP6, to the plasma membrane. Essential for specification of embryonic polarity and mesoderm induction. Monomer. Interacts with LRP5; the interaction prevents LRP5 from forming aggregates and chaperones LRP6 to the plasma membrane. Interacts with LRP6; the interaction prevents LRP6 from forming aggregates and chaperones LRP6 to the plasma membrane. Belongs to the MESD family. Note: This description may include information from UniProtKB.