|WikiProject Molecular and Cell Biology||(Rated Start-class, Low-importance)|
|WikiProject Medicine||(Rated Start-class, Low-importance)|
|The content of Circulating microvesicle was merged into Microvesicles on 7 November 2017. For the contribution history and old versions of the redirected page, please see ; for the discussion at that location, see its talk page.|
Microvesicles are fragments of plasma membrane ranging from 0,1-1µm shed from almost all cell types during activation. They originate directly from the plasma membrane of the cell and reflect the antigenic content of the cells which they originate from. Recently scientifics found that microvesicles can deliver mRNA from cells let speculate on their possible role on cel-to-cell exchange of genetic material.
Mechanisms of shedding of MV
Under physiologic condition, the plasma membrane of cells has an asymetric distribution of their phospholipids. Aminophospholipids, phosphatidylserine and phosphatidilethanolammine, are specifically sequestered in the inner leaflet of the membrane. The transbilayer lipid distribution is under the control of 3 phospholipidic pumps: an inward-directed pump, a flippase, an outward-directed pump, or floppase and a lipid scramblase, responsible for a non specific redistribution of lipids across the membrane. After cell stimulation, including apoptosis, a subsequent cytosolic Ca2+ increase, promotes the lost of the phospholipids asymmetry of the plasma membrane, subsequent phosphatidylserine exposure and there is a transient phospholipidic inbalance between the external leaflet at the expense of the inner leaflet leading blebbing of the plasmamembrane and microvesicles release.
Relationship with exosomes
The distinction between exosomes and microvesicles seems muddy even in literature, but it should be explained and justified even if it seems increasingly likely that they are the same thing.Cyrux (talk) 20:24, 23 December 2011 (UTC)
- Incredibly muddled, you're right. But there is a distinction, even if the nomenclature (or its usage) doesn't always represent it correctly. Exosomes are released into internal compartments, then into the extracellular environment when the compartments fuse with the plasma membrane. Microvesicles derive directly from the plasma membrane. Exosomes are about 30-150 nM in diameter; microvesicles are around 80 nM and up, so there is some size overlap. Both are subsets of "microparticles." SpectraValor (talk) 22:43, 2 March 2012 (UTC)
As far as I can tell from reading these two articles, microvesicles are the same thing as circulating microvesicles. So I suggest merging them into the more general-sounding article, "microvesicles". --DavidCary (talk) 02:28, 8 May 2015 (UTC)
- I support the proposed merger. I would also suggest "extracellular vesicle" as a higher level article that would include microvesicle and exosome. I noticed the term "cMV" was used in the other article for "circulating microvesicle". In the biology literature, CMV is cytomegalovirus. SlightlySourAle (talk) 16:11, 19 August 2016 (UTC)