Multivesicular bodies: biogenesis and function

Article By:

Piper, Robert C. Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa.

Last reviewed:2013

DOI:https://doi.org/10.1036/1097-8542.YB130004

Multivesicular bodies (MVBs) or multivesicular endosomes are synonymous with late endosomes. Transport vesicles derived from the plasma membrane fuse to form early endosomes, which in turn undergo fission and fusion events to mature into late endosomes that eventually fuse with lysosomes (see illustration). The distinguishing characteristic of MVBs is that they contain vesicles and other membranes within their lumen [intraluminal vesicles (ILVs)], which are contained within a single limiting membrane bilayer. ILVs begin accumulating in early endosomes and continue to accumulate until the late endosome stage. Fusion of late endosomes with lysosomes allows for the degradation of ILVs and their contents. Alternatively, in some cases, MVBs may fuse with the plasma membrane to allow secretion of ILVs into the extracellular milieu. MVBs can also serve as intermediates in the formation of more specialized lysosome-related organelles, such as melanosomes or lytic granules, where components enveloped into ILVs are used to form some of the intraluminal constituents of these organelles. A variety of trafficking pathways can contribute to the formation of ILVs, reflecting the fact that MVBs and the ILVs within them fulfill a variety of cellular roles.

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