Membrane curvature controls dynamin polymerization
Membrane curvature controls dynamin polymerization
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DOI：
10.1073/pnas.0913734107
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发表时间：
2010-03-02
影响因子：
11.1
通讯作者：
Bassereau, Patricia
中科院分区：
文献类型：
--
作者：
Roux, Aurelien;Koster, Gerbrand;Bassereau, Patricia
细胞内运输过程中膜曲率的产生涉及到许多能够弯曲脂质双层的蛋白质。其中，动力蛋白样蛋白被证明可以使膜变形成小管，到目前为止是唯一已知的以机械方式驱动膜分裂的蛋白质。因为动力蛋白在膜小管周围形成一层螺旋状的涂层，它的聚合被认为是造成这种膜变形的原因。在这里，我们证明了动力蛋白聚合产生的力，18pN，足以使膜变形，但仍然可以被高的膜张力所抵消。重要的是，我们观察到在较低的动力浓度下，聚合物的成核强烈地依赖于膜的曲率。这表明动力素可能被精确地招募到膜芽的脖子上，因为它们的曲率很高。为了理解这种曲率依赖关系，我们发展了一个基于动力蛋白聚合和膜机械变形之间竞争的理论。动力蛋白聚合的这种曲率控制是在特定的浓度范围内(类似于0.1-10微米)预测的，这与我们的测量结果相一致。更广泛地说，我们预计任何以曲率耦合的方式结合或自组装到膜上的蛋白质的行为应该在性质上相似，但具有自己特定的浓度范围。
The generation of membrane curvature in intracellular traffic involves many proteins that can curve lipid bilayers. Among these, dynamin-like proteins were shown to deform membranes into tubules, and thus far are the only proteins known to mechanically drive membrane fission. Because dynamin forms a helical coat circling a membrane tubule, its polymerization is thought to be responsible for this membrane deformation. Here we show that the force generated by dynamin polymerization, 18 pN, is sufficient to deform membranes yet can still be counteracted by high membrane tension. Importantly, we observe that at low dynamin concentration, polymer nucleation strongly depends on membrane curvature. This suggests that dynamin may be precisely recruited to membrane buds' necks because of their high curvature. To understand this curvature dependence, we developed a theory based on the competition between dynamin polymerization and membrane mechanical deformation. This curvature control of dynamin polymerization is predicted for a specific range of concentrations (similar to 0.1-10 mu M), which corresponds to our measurements. More generally, we expect that any protein that binds or self-assembles onto membranes in a curvature-coupled way should behave in a qualitatively similar manner, but with its own specific range of concentration.