Polarization of actin cytoskeleton is reduced in dendritic protrusions during early spine development in hippocampal neuron.
Polarization of actin cytoskeleton is reduced in dendritic protrusions during early spine development in hippocampal neuron.
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DOI：
10.1091/mbc.e12-02-0165
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发表时间：
2012-08
影响因子：
3.3
通讯作者：
Yu J
中科院分区：
文献类型：
--
作者：
Tatavarty V;Das S;Yu J
这是第一次测量树突丝状伪足（1.20 µm/min），树突棘的前体和新形成的棘（0.03 µm/min）中的F-肌动蛋白逆行流速。这种差异表明在棘发生过程中力产生机制的重塑。还发现肌球蛋白II在调节F-肌动蛋白流动中起作用。树突棘是在神经元网络中接收突触信号的小突起。肌动蛋白细胞骨架在调节脊柱形态发生以及突触功能中起关键作用。在这里，我们报告的第一个定量测量的F-肌动蛋白逆行流速在树突状丝状伪足，树突棘的前体，并在新形成的棘，使用基于光活化定位显微镜的技术。我们发现了一个快速的F-肌动蛋白逆行流的树突丝状伪足，但不是在脊柱颈部。F-肌动蛋白流速的定量，结合光漂白测量后的荧光恢复，允许空间分辨的肌动蛋白周转率的动力学速率，这是以前不可行的一个完整的量化。此外，我们提供的证据表明，肌球蛋白II调节肌动蛋白流动的树突丝状伪足和易位从基地到尖端的突起后，棘形成。Rac 1抑制导致肌球蛋白II的错误定位，以及破坏F-肌动蛋白流。这些结果提供了进步的定量理解的F-肌动蛋白重塑过程中脊柱形成。
This is the first measurement of F-actin retrograde flow rate in dendritic filopodia (1.20 µm/min), the precursor of dendritic spines, and in newly formed spines (0.03 µm/min). The difference indicates a remodeling of the force-generation mechanism during spinogenesis. It is also found that myosin II plays a role in regulating F-actin flow. Dendritic spines are small protrusions that receive synaptic signals in neuronal networks. The actin cytoskeleton plays a key role in regulating spine morphogenesis, as well as in the function of synapses. Here we report the first quantitative measurement of F-actin retrograde flow rate in dendritic filopodia, the precursor of dendritic spines, and in newly formed spines, using a technique based on photoactivation localization microscopy. We found a fast F-actin retrograde flow in the dendritic filopodia but not in the spine necks. The quantification of F-actin flow rates, combined with fluorescence recovery after photobleaching measurements, allowed for a full quantification of spatially resolved kinetic rates of actin turnover, which was not previously feasible. Furthermore we provide evidences that myosin II regulates the actin flow in dendritic filopodia and translocates from the base to the tip of the protrusion upon spine formation. Rac1 inhibition led to mislocalization of myosin II, as well as to disruption of the F-actin flow. These results provide advances in the quantitative understanding of F-actin remodeling during spine formation.