BIOL 2021 Chapter Notes - Chapter 13.5: Cholesteryl Ester, Cell Membrane, Coronary Circulation
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E(cid:374)doso(cid:373)es & retur(cid:374)ed to plas(cid:373)a me(cid:373)(cid:271)ra(cid:374)e: to via late endosomes to lysosomes. Ldl dissociate from receptors in acidic environment of early endosomes. Ldl ends in endolysosomes & lysosomes, where it is degraded to release free cholesterol. Ldl receptors are returned to plasma membrane via transport vesicles that bud off from tubular regions of early endosome. He is recycling transport vesicles bud from early endosomes which returns ldl receptors directly to plasma membrane: transferring receptor recycles its receptors & ligand. Transferrin is soluble protein that carries iron in blood. Cell surface transferring receptors deliver transferring with iron bound to early endosomes by receptor mediated endocytosis. Low ph of endosomes induces transferring to release bound iron. Receptor-apotransferring complex is recycled back to plasma membrane. When apotransferring returns to neutral ph of extracellular fluid, transferring dissociates from receptor & freed to pickup more fe.