- published: 18 May 2016
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The vault or vault cytoplasmic ribonucleoprotein is a eukaryotic organelle whose function is not fully understood. Discovered and successfully isolated by cell biologist Nancy Kedersha and biochemist Leonard Rome of the UCLA School of Medicine in the 1980s, vaults are cytoplasmic organelles which under an electron microscope resemble the arches of a cathedral vault, with 39-fold symmetry. They are present in many types of eukaryotic cells and appear to be highly conserved amongst eukaryotes. Vaults become part of lipid rafts where they may play a role fighting pathogens.
Vaults are large ribonucleoprotein particles. About 3 times the size of a ribosome and weighing approximately 13 MDa, they are found in many diverse eukaryotic cells. They measure 34 nm by 60 nm from a negative stain, 26 nm by 49 nm from cryo-electron microscopy, and 35 nm by 59 nm from STEM. The vaults consist primarily of proteins, making it difficult to stain with conventional techniques. The protein structure consists of many major vault proteins (MVP) bound to one of the two minor vault proteins. Two large complexes of several MVP's and a minor vault protein close together to form the barrel-like vault organelle. They also contain small vault RNAs (vRNAs) of 86–141 bases within.
Vault may refer to:
In cell biology, an organelle ( /ɔrɡəˈnɛl/) is a specialized subunit within a cell that has a specific function, and is usually separately enclosed within its own lipid bilayer.
The name organelle comes from the idea that these structures are to cells what an organ is to the body (hence the name organelle, the suffix -elle being a diminutive). Organelles are identified by microscopy, and can also be purified by cell fractionation. There are many types of organelles, particularly in eukaryotic cells. Prokaryotes were once thought not to have organelles, but some examples have now been identified.
In biology organs are defined as confined functional units within an organism. The analogy of bodily organs to microscopic cellular substructures is obvious, as from even early works, authors of respective textbooks rarely elaborate on the distinction between the two.
Credited as the first to use a diminutive of organ (i.e. little organ) for cellular structures was German zoologist Karl August Möbius (1884), who used the term "organula" (plural form of organulum, the diminutive of latin organum). From the context, it is clear that he referred to reproduction related structures of protists. In a footnote, which was published as a correction in the next issue of the journal, he justified his suggestion to call organs of unicellular organisms "organella" since they are only differently formed parts of one cell, in contrast to multicellular organs of multicellular organisms. Thus, the original definition was limited to structures of unicellular organisms.