Department of Neuroscience, DBRM, Karolinska Institutet, 17177 Stockholm, Sweden.
J Cell Sci. 2011 Jan 1;124(Pt 1):133-43. doi: 10.1242/jcs.072686.
Clathrin-mediated vesicle recycling in synapses is maintained by a unique set of endocytic proteins and interactions. We show that endophilin localizes in the vesicle pool at rest and in spirals at the necks of clathrin-coated pits (CCPs) during activity in lamprey synapses. Endophilin and dynamin colocalize at the base of the clathrin coat. Protein spirals composed of these proteins on lipid tubes in vitro have a pitch similar to the one observed at necks of CCPs in living synapses, and lipid tubules are thinner than those formed by dynamin alone. Tubulation efficiency and the amount of dynamin recruited to lipid tubes are dramatically increased in the presence of endophilin. Blocking the interactions of the endophilin SH3 domain in situ reduces dynamin accumulation at the neck and prevents the formation of elongated necks observed in the presence of GTPγS. Therefore, endophilin recruits dynamin to a restricted part of the CCP neck, forming a complex, which promotes budding of new synaptic vesicles.
网格蛋白介导的囊泡在突触中的循环是由一组独特的内吞蛋白和相互作用维持的。我们发现，在七鳃鳗突触的活动过程中，网格蛋白包被凹陷（CCP）颈部的螺旋结构中，内收蛋白在休息时位于囊泡池中，在活动时位于囊泡池中。内收蛋白和动力蛋白在网格蛋白外壳的底部共定位。体外由这些蛋白在脂质管上组成的蛋白螺旋具有与活突触中 CCP 颈部观察到的螺旋相似的螺距，并且脂质小管比单独由动力蛋白形成的小管薄。在存在内收蛋白的情况下，管腔化效率和招募到脂质管的动力蛋白数量显著增加。在体内阻断内收蛋白 SH3 结构域的相互作用会减少颈部的动力蛋白积累，并防止在 GTPγS 存在下观察到的伸长颈部的形成。因此，内收蛋白将动力蛋白募集到 CCP 颈部的受限部分，形成促进新突触小泡出芽的复合物。
