Sandbox Reserved 1495
From Proteopedia
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== Function == | == Function == | ||
| - | Communication beetween the different compartiments of eukaryotic cell and plasma membrane is allowed by vesicles, which convey molecules within the cytoplasm. Clathrin are involved in the formation of those vesicles in a process named clathrin mediated endocytosis. Clathrins form a skeleton around the vesicle once several | + | Communication beetween the different compartiments of eukaryotic cell and plasma membrane is allowed by vesicles, which convey molecules (called cargos) within the cytoplasm. Clathrin are involved in the formation of those vesicles in a process named clathrin mediated endocytosis. However this process refers only to intake through vesicles from the plasma membrane. Clathrins form a skeleton around the vesicle once several triskelia are assembled. The coated vesicle like so formed will then lose its round protein skeleton after its departure from the initial compartment because the clathrin cage is quickly dismantled. |
This phenomena proceeds through five stages: initiation, cargo selection, coat assembly, scission and uncoating. During the cargo selection and the initiation, clathrins polymerize into hexagons and pentagons. The ratio between these two shapes dependents of the cells' curve. | This phenomena proceeds through five stages: initiation, cargo selection, coat assembly, scission and uncoating. During the cargo selection and the initiation, clathrins polymerize into hexagons and pentagons. The ratio between these two shapes dependents of the cells' curve. | ||
Revision as of 15:53, 11 January 2019
Contents |
Generalities
Clathrin is a 3 legged cytoplasmic protein with 3 heavy chains and 3 light chains. It has a triskelion shape (A tryskelion consists of three bent limbs radiating from a centre) and can self-assembled into a polyhedral structure arround [vesicles] of eukaryotic cells. Triskelia can polymerize into cages or even flat lattice, depending on the ratio hexagon/pentagon formed during the process.
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Function
Communication beetween the different compartiments of eukaryotic cell and plasma membrane is allowed by vesicles, which convey molecules (called cargos) within the cytoplasm. Clathrin are involved in the formation of those vesicles in a process named clathrin mediated endocytosis. However this process refers only to intake through vesicles from the plasma membrane. Clathrins form a skeleton around the vesicle once several triskelia are assembled. The coated vesicle like so formed will then lose its round protein skeleton after its departure from the initial compartment because the clathrin cage is quickly dismantled. This phenomena proceeds through five stages: initiation, cargo selection, coat assembly, scission and uncoating. During the cargo selection and the initiation, clathrins polymerize into hexagons and pentagons. The ratio between these two shapes dependents of the cells' curve.
Relevance
Endocytosis is essential to neurotransmission, as well to signal transduction and more generally to the regulation of many plasma membrane activities and is thus essential to eukaryotic life. Indeed, clathrins are shown as a active player in the recycling of synaptics vesicles, they are nessecaryl to the good functionement of synaptic transmission.
Structural highlights
The formation of clathrin basket is not spontaneous, there are proteins necessary to form this shape. These accessories proteins called adaptors proteins fixe themselves to the N-terminal (bêta)-propeller domain of clathrin heavy chain. Theremore, with these proteins there are arrestins and Hsc70 which associate to the N-terminal (bêta)-propeller domain of clathrin heavy chain. Then, this part of the chain links to another part of the heavy chain leg. This step causes the subdivision of the distal and proximal domains with a kind of flexible knee link between them.
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References
Molecular mechanism and physiological functions of clathrin‑mediated endocytosisVOLUME 12 | AUGUST 2011 Harvey T. McMahon and Emmanuel Boucrot VOLUME 12 | AUGUST 2011
