▁different ▁AP ▁complex es ▁in ▁m amm als . ▁AP 1 ▁is ▁responsible ▁for ▁the ▁transport ▁of ▁l ys os om al ▁hyd rol ases ▁between ▁the ▁trans - G ol gi ▁network , ▁and ▁end os om es . ▁AP 2 ▁adapt or ▁complex ▁associ ates ▁with ▁the ▁pl asma ▁memb rane ▁and ▁is ▁responsible ▁for ▁end oc yt osis . ▁AP 3 ▁is ▁responsible ▁for ▁protein ▁tra ff ick ing ▁to ▁l ys os om es ▁and ▁other ▁related ▁organ elles . ▁AP 4 ▁is ▁less ▁well ▁character ised . ▁AP ▁complex es ▁are ▁heter ot et ram ers ▁composed ▁of ▁two ▁large ▁sub un its ▁( ada pt ins ), ▁a ▁medium ▁sub unit ▁( mu ) ▁and ▁a ▁small ▁sub unit ▁( sigma ). ▁For ▁example , ▁in ▁AP 1 ▁these ▁sub un its ▁are ▁g amma - 1 - ada pt in , ▁beta - 1 - ada pt in , ▁mu - 1 ▁and ▁s igma - 1 , ▁while ▁in ▁AP 2 ▁they ▁are ▁alpha - ada pt in , ▁beta - 2 - ada pt in , ▁mu - 2 ▁and ▁s igma - 2 . ▁Each ▁sub unit ▁has ▁a ▁specific ▁function . ▁Ada pt ins ▁recogn ise ▁and ▁bind ▁to ▁cl ath rin ▁through ▁their ▁h inge ▁region ▁( cl ath rin ▁box ), ▁and ▁rec ruit ▁access ory ▁prote ins ▁that ▁mod ulate ▁AP ▁function ▁through ▁their ▁C - term inal ▁ear ▁( append age ) ▁domains . ▁Mu ▁recogn ises ▁ty