Dynamics of myristoylated amino-terminal domain of Src in the plasma membrane of mechano-stimulated cells studied by single molecule imaging

Src是机械转导的关键信号分子。施加在细胞上的机械刺激可以诱导Src快速激活，但机械刺激如何激活Src分子仍不清楚。本研究在单分子水平上观察了活细胞质膜中荧光标记的Src肉豆酰化氨基端，以研究Src氨基端脂质部分在其动力学和活化中的作用。观察到大多数探针在膜中迅速扩散，但相当一部分分子表现出时间固定。我们还发现它们的固定经常发生在局灶粘连（FAs）附近，并且它是机械和胆固醇依赖的。这些结果表明，Src氨基末端的脂质部分可能通过与质膜脂质微域的相互作用，在FAs周围Src分子的动力学和激活中起关键作用。

Src is a critical signaling molecule for mechanotransduction. Mechanical stimuli applied on the cell can induce a rapid Src activation, but it remains largely unknown how mechanical stimuli activates Src molecules. Here, we observed fluorescently labeled myristoylated amino terminus of Src in the plasma membrane of living cells at the single molecule level to examine the role of lipid moiety of the amino terminus of Src on its dynamics and activation. Most probes were observed to diffuse rapidly in the membrane, but that significant fraction of the molecules exhibited temporal immobilization. We also found that the immobilization of them occurred frequently in the proximity of focal adhesions (FAs), and that it was mechano- and cholesterol-dependent. These results suggest that lipid moiety of the amino terminus of Src may play a critical role in the dynamics and activation of Src molecules around FAs through the interaction with lipid micro domains of the plasma membrane.