21. D12, the mouse homolog of MDS032, is a Golgi secretory apparatus and with endosome -lysosome transport. 22. Rab5 contributes to early endosome fusion that works through the coordination of other effector proteins, as mentioned above. 23. It is because of these vesicles that the endosome is sometimes known as a " multivesicular body ". 24. The major function of the gp64 envelope protein is to cause the pH-mediated envelope fusion to the endosome . 25. The pH in the late endosome can reach 6.0, which causes dissociation of M6P from its receptor. 26. Inside the endosome , the toxin is split by a trypsin-like protease into its individual A and B fragments. 27. This gene encodes a protein involved in endosomal sorting of cell surface receptors via a multivesicular body / late endosome pathway. 28. Exosomes are formed by invagination within a cell to create an intracellular vesicle called an endosome , or an endocytic vesicle. 29. The cell then attempts to begin digesting the contents of the endosome by acidifying its interior and transforming it into a lysosome. 30. The MPRs are packed into vesicles that bud off the late endosome and return to the " trans "-Golgi network.