Single-molecule force spectroscopy of the Aplysia cell adhesion molecule reveals two homophilic bonds.
Single-molecule force spectroscopy of the Aplysia cell adhesion molecule reveals two homophilic bonds.
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DOI：
10.1016/j.bpj.2012.07.004
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发表时间：
2012-08
影响因子：
3.4
通讯作者：
Elena Martines;Jian Zhong;Julien Muzard;Aih Cheun Lee;B. Akhremitchev;Daniel M. Suter;Gil U. Lee
中科院分区：
文献类型：
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作者：
Elena Martines;Jian Zhong;Julien Muzard;Aih Cheun Lee;B. Akhremitchev;Daniel M. Suter;Gil U. Lee
加州巨瘤包括一个强大的模型系统，用于定量分析细胞和生物物理特性，这些特性对神经元的发育和功能至关重要。细胞黏附分子（apCAM）是细胞黏附分子免疫球蛋白超家族的一员，存在于生长锥质膜中，参与神经突生长、突触形成和突触可塑性。apCAM被认为是脊椎动物神经细胞粘附分子（NCAM）的应用同源物；然而，由于缺乏apCAM细胞外部分的详细结合数据，apCAM是否具有类似的结合特性和神经元功能尚未完全确定。在这项工作中，我们使用原子力显微镜对apCAM的细胞外区域进行了单分子力谱分析，并首次（据我们所知）表明apCAM与NCAM一样确实是一种亲同质细胞粘附分子。此外，与NCAM一样，apCAM在转构型中表现出两种不同的键，尽管apCAM键的动力学和结构参数与NCAM有很大不同。综上所述，这些单分子分析进一步表明apCAM和NCAM是同源物种，可能具有相似的功能。
Aplysia californicaneurons comprise a powerful model system for quantitative analysis of cellular and biophysical properties that are essential for neuronal development and function. TheAplysiacell adhesion molecule (apCAM), a member of the immunoglobulin superfamily of cell adhesion molecules, is present in the growth cone plasma membrane and involved in neurite growth, synapse formation, and synaptic plasticity. apCAM has been considered to be theAplysiahomolog of the vertebrate neural cell adhesion molecule (NCAM); however, whether apCAM exhibits similar binding properties and neuronal functions has not been fully established because of the lack of detailed binding data for the extracellular portion of apCAM. In this work, we used the atomic force microscope to perform single-molecule force spectroscopy of the extracellular region of apCAM and show for the first time (to our knowledge) that apCAM, like NCAM, is indeed a homophilic cell adhesion molecule. Furthermore, like NCAM, apCAM exhibits two distinct bonds in thetransconfiguration, although the kinetic and structural parameters of the apCAM bonds are quite different from those of NCAM. In summary, these single-molecule analyses further indicate that apCAM and NCAM are species homologs likely performing similar functions.