|
Membrane vesicle trafficking in ''eukaryotic'' animal cells involves movement of important biochemical signal molecules from synthesis-and-packaging locations in Golgi body to specific 'release' locations on the inside of the plasma membrane of the secretory cell, in the form of Golgi membrane-bound micro-sized vesicles, termed ''membrane vesicles'' (MVs). In this process, the 'packed' cellular products are released/secreted outside the cell across plasma membrane. However, vesicular membrane is retained and recycled by the secretory cells. This phenomenon has key role in synaptic neurotransmission, endocrine secretion, mucous secretion, granular-product secretion by neutrophils,etc. The scientists behind this discovery were awarded Nobel prize for the year 2013. In the ''prokaryotic'' gram-negative bacterial cells, membrane vesicle trafficking is mediated via bacterial outer membrane bounded nano-sized vesicles, called bacterial outer membrane vesicles, (OMVs)(Fig.1). In this case, however, the OMV membrane is secreted as well, along with OMV-contents to outside the secretion-active bacterium. This phenomenon has key role in host-pathogen interactions, endotoxic shock in patients, invasion and infection of animals/plants, inter-species bacterial competition, qourum sensing, exocytosis,etc.(see External Links). == Membrane vesicle trafficking in Eukaryotes == a. ''Intracellular'' trafficking occurs between subcellular compartments like Golgi cisternae and multivesicular endosomes for transport of soluble proteins as MVs. b. ''Budding'' of MVs directly from plasma membrane as ''microvesicles'' released outside the secretory cells. c. ''Exosomes'' are MVs that can form inside an internal compartment like multivesicular endosome. Exosomes are released eventually due to fusion of this endosome with plasma membrane of cell. d. ''Hijacking'' of exosomal machinery by some viruses like retroviruses, wherein viruses bud inside multivesicular endosomes and get secreted subsequently as exosomes. All these types (a-d) of modes of membrane vesicle trafficking, taking place in eukaryotic cells have been explained diagrammatically.〔Thery C., Ostrowsky M. and Segura E. (2009) Membrane vesicles as conveyors of immuno responses. ''Nature Reviews Immunology'', vol. 9, pp. 581-593. http://www.nature.com/nri/journal/v9/n8/fig_tab/nri2567_F1.html〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「membrane vesicle trafficking」の詳細全文を読む スポンサード リンク
|