Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-32, India.
Infectious Diseases and Immunology Division, Indian Institute of Chemical Biology, Kolkata-32, India.
J Biol Chem. 2013 Mar 15;288(11):7815-7828. doi: 10.1074/jbc.M112.417196. Epub 2013 Jan 25.
The functional role of the C2 insert of nonmuscle myosin II-C (NM II-C) is poorly understood. Here, we report for the first time that the expression of the C2 insert-containing isoform, NM II-C1C2, is inducible in Neuro-2a cells during differentiation both at mRNA and protein levels. Immunoblot and RT-PCR analysis reveal that expression of NM II-C1C2 peaks between days 3 and 6 of differentiation. Localization of NM II-C1C2 in Neuro-2a cells suggests that the C2 insert-containing isoform is localized in the cytosol and along the neurites, specifically at the adherence point to substratum. Inhibition of endogenous NM II-C1C2 using siRNA decreases the neurite length by 43% compared with control cells treated with nonspecific siRNA. Time lapse image analysis reveals that neurites of C2-siRNA-treated cells have a net negative change in neurite length per minute, leading to a reduction of overall neurite length. During neuritogenesis, NM II-C1C2 can interact and colocalize with β1-integrin in neurites. Altogether, these studies indicate that NM II-C1C2 may be involved in stabilizing neurites by maintaining their structure at adhesion sites.
非肌肉肌球蛋白 II-C（NM II-C）的 C2 插入片段的功能作用知之甚少。在这里，我们首次报道了在分化过程中，Neuro-2a 细胞中 NM II-C1C2 包含 C2 插入片段的同工型的表达在 mRNA 和蛋白质水平上都是可诱导的。免疫印迹和 RT-PCR 分析显示，NM II-C1C2 的表达在分化的第 3 天到第 6 天之间达到峰值。NM II-C1C2 在 Neuro-2a 细胞中的定位表明，包含 C2 插入片段的同工型定位于细胞质和神经突中，特别是在与基质附着的粘附点处。与用非特异性 siRNA 处理的对照细胞相比，使用 siRNA 抑制内源性 NM II-C1C2 会使神经突长度减少 43%。延时成像分析显示，C2-siRNA 处理的细胞的神经突的神经突长度每分钟有净负变化，导致总体神经突长度减少。在神经突生成过程中，NM II-C1C2 可以与神经突中的β1-整合素相互作用并共定位。总之，这些研究表明 NM II-C1C2 可能通过维持其在粘附部位的结构来稳定神经突。
