, ▁imm une ▁function ing , ▁stress ▁response , ▁and ▁the ▁transport ▁of ▁f ats ▁in ▁the ▁blood stream . ▁ ▁Meg alin ▁is ▁embedded ▁in ▁the ▁memb rane ▁of ▁cells ▁that ▁line ▁the ▁surfaces ▁and ▁cav ities ▁of ▁the ▁body ▁( ep ith el ial ▁cells ). ▁The ▁re ceptor ▁helps ▁move ▁its ▁lig ands ▁from ▁the ▁cell ▁surface ▁into ▁the ▁cell ▁( end oc yt osis ). ▁It ▁is ▁active ▁in ▁the ▁development ▁and ▁function ▁of ▁many ▁parts ▁of ▁the ▁body , ▁including ▁the ▁brain ▁and ▁sp inal ▁cord ▁( central ▁nerv ous ▁system ), ▁eyes , ▁ears , ▁l ungs , ▁int est ine , ▁re product ive ▁system , ▁and ▁the ▁small ▁tub es ▁in ▁the ▁kid ne ys ▁where ▁ur ine ▁is ▁formed ▁( ren al ▁tub ules ). ▁ ▁L R P 2 ▁gene ▁mut ations ▁that ▁cause ▁Don na i – B arrow ▁synd rome ▁are ▁believed ▁to ▁result ▁in ▁the ▁absence ▁of ▁functional ▁meg alin ▁protein . ▁The ▁lack ▁of ▁functional ▁meg alin ▁in ▁the ▁ren al ▁tub ules ▁causes ▁meg alin ' s ▁various ▁lig ands ▁to ▁be ▁ex cret ed ▁in ▁the ▁ur ine ▁rather ▁than ▁being ▁absor bed ▁back ▁into ▁the ▁blood stream . ▁The ▁features ▁of ▁Don na i – B arrow ▁synd rome ▁are ▁probably ▁caused ▁by ▁the ▁in ability ▁of ▁meg alin ▁to ▁help ▁abs orb ▁these ▁lig ands , ▁dis ruption ▁of ▁bio chem ical ▁signal ing ▁path ways , ▁or ▁other ▁effects ▁of ▁the ▁non function al