Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Queensland 4072, Australia; Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia.
Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia.
Mol Cell Neurosci. 2017 Oct;84:100-111. doi: 10.1016/j.mcn.2017.07.005. Epub 2017 Aug 7.
In neurosecretory cells, myosin VI associated with secretory granules (SGs) mediates their activity-dependent recruitment to the cortical actin network and is necessary to sustain exocytosis. The mechanism by which myosin VI interacts with SGs is unknown. Using a myosin VI pull-down assay and mass spectrometry we identified Mena, a member of the ENA/VASP family, as a myosin VI binding partner in PC12 cells, and confirmed that Mena colocalized with myosin VI on SGs. Using a knock-sideways approach to inactivate the ENA/VASP family members by mitochondrial relocation, we revealed a concomitant redistribution of myosin VI. This was ensued by a reduction in the association of myosin VI with SGs, a decreased SG mobility and density in proximity to the plasma membrane as well as decreased evoked exocytosis. These data demonstrate that ENA/VASP proteins regulate SG exocytosis through modulating the activity of myosin VI.
在神经分泌细胞中，与分泌颗粒（SGs）相关的肌球蛋白 VI 介导其依赖于活性的募集到皮质肌动蛋白网络，并且是维持胞吐作用所必需的。肌球蛋白 VI 与 SGs 相互作用的机制尚不清楚。使用肌球蛋白 VI 下拉测定和质谱法，我们在 PC12 细胞中鉴定出 ENA/VASP 家族的成员 Mena 作为肌球蛋白 VI 的结合伴侣，并证实 Mena 与肌球蛋白 VI 在 SG 上共定位。通过线粒体重定位对 ENA/VASP 家族成员进行敲侧法失活，我们揭示了肌球蛋白 VI 的伴随再分布。随后，与 SG 的结合减少，靠近质膜的 SG 迁移性和密度降低，以及诱发的胞吐作用降低。这些数据表明，ENA/VASP 蛋白通过调节肌球蛋白 VI 的活性来调节 SG 胞吐作用。
