Polar Chemoreceptor Clustering by Coupled Trimers of Dimers
Polar Chemoreceptor Clustering by Coupled Trimers of Dimers
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DOI：
10.1016/j.bpj.2008.10.021
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发表时间：
2009-01-21
影响因子：
3.4
通讯作者：
Endres, Robert G.
中科院分区：
文献类型：
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作者：
Endres, Robert G.
细菌趋化性的受体在细胞极点形成簇，在那里簇起到“天线”的作用，放大配体浓度的微小变化。值得注意的是，化学感受器在多个长度尺度上聚集。在最小的范围内，受体形成二聚体，二聚体组装成稳定的二聚体计时器。在大范围内，三聚体形成由数千个受体组成的大的极簇。虽然对受体簇产生的信号特性已知很多，但尚不清楚受体如何定位于细胞极点，以及决定簇大小的因素是什么。在这里，我们提出了一个基于晚餐的偶联三聚体的极性受体聚集模型，其中簇的大小被确定为簇膜自由能的最小值。这种能量来自团簇-膜弹性能，由于大团簇的高固有曲率而惩罚大团簇，以及有利于大团簇的受体-受体耦合。我们发现，弯曲细胞极点处团簇-膜曲率失配的减少导致了更大和更强健的极性团簇，这与实验观察一致，而侧向团簇则被有效地抑制。
Receptors of bacterial chemotaxis form clusters at the cell poles, where clusters act as "antennas" to amplify small changes in ligand concentration. It is worthy of note that chemoreceptors cluster at multiple length scales. At the smallest scale, receptors form dimers, which assemble into stable timers of dimers. At a large scale, trimers form large polar clusters composed of thousands of receptors. Although much is known about the signaling properties emerging from receptor clusters, it is unknown how receptors localize at the cell poles and what the determining factors are for cluster size. Here, we present a model of polar receptor clustering based on coupled trimers of dinners, where cluster size is determined as a minimum of the cluster-membrane free energy. This energy has contributions from the cluster-membrane elastic energy, penalizing large clusters due to their high intrinsic curvature, and receptor-receptor coupling that favors large clusters. We find that the reduced cluster-membrane curvature mismatch at the curved cell poles leads to large and robust polar clusters, in line with experimental observation, whereas lateral clusters are efficiently suppressed.