Alpha 7 beta 1 integrin is a component of the myotendinous junction on skeletal muscle.
Alpha 7 beta 1 integrin is a component of the myotendinous junction on skeletal muscle.
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发表时间：
1993-10
影响因子：
4
通讯作者：
Z. Bao;M. Lakonishok;S. Kaufman;A. Horwitz
中科院分区：
文献类型：
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作者：
Z. Bao;M. Lakonishok;S. Kaufman;A. Horwitz
针对与骨骼肌整联蛋白共同纯化的70kDa条带进行免疫，产生了一种针对禽类α7整联蛋白亚基的抗体。通过组织染色模式以及与针对大鼠α7胞质结构域的抗体的交叉反应性，确定了该抗体的特异性。在成年骨骼肌切片上，α7整联蛋白在肌 - 腱连接处（MTJ）富集。这种定位是独特的，因为α1、α3、α5、α6和αv亚基均不在肌 - 腱连接处定位。在胚胎发育过程中对α7亚基在MTJ中的分布进行了检测。在胚胎第14天左右，连接处首次出现α7表达，并且在此阶段几乎仅在发育中的MTJ处。在较早的胚胎（11天）中，α3在连接区域周围呈独特的点状染色表达。α7亚基在MTJ中出现的时间与肌原纤维插入肌膜下密度以及连接膜的折叠相关，这表明α7整联蛋白在此过程中起作用。纽蛋白在肌 - 腱连接的整个发育过程中都存在，这表明α7整联蛋白识别一种预先形成的细胞骨架结构。α7亚基在肌 - 腱连接处以及α5亚基在黏着斑中的存在表明了这两种黏附连接之间的分子差异。这也指出了肌肉上连接特异性的可能起源。利用一种抗磷酸酪氨酸（PY20）的抗体进一步探究了这两种连接之间的差异。磷酸酪氨酸被认为参与了黏附的组织和稳定。黏着斑和神经肌肉接头含有酪氨酸磷酸化的蛋白质，但MTJ中没有。
Immunization against a 70 kDa band that co-purifies with skeletal muscle integrins has resulted in an antibody directed against the avain alpha 7 integrin subunit. The specificity of the antibody was established by patterns of tissue staining and cross-reactivity with antibodies directed against the cytoplasmic domain of the rat alpha 7 cytoplasmic domain. On sections of adult skeletal muscle the alpha 7 integrin was enriched in the myotendinous junction (MTJ). This localization was unique as neither the alpha 1, alpha 3, alpha 5, alpha 6 and alpha v subunit localizes in the myotendinous junction. The distribution of the alpha 7 subunit in the MTJ was examined during embryonic development. alpha 7 expression in the junction is first apparent around embryo day 14 and is almost exclusively at the developing MTJ at this stage. alpha 3 is expressed with distinctive punctate staining around the junctional area in earlier embryos (11-day). The time of appearance of the alpha 7 subunit in the MTJ correlates with the insertion of myofibrils into subsarcolemmal densities and folding of the junctional membrane, suggesting a role of the alpha 7 integrin in this process. Vinculin is present throughout development of the myotendinous junction, suggesting that the alpha 7 integrin recognizes a preformed cytoskeletal structure. The presence of the alpha 7 subunit in the myotendinous junction and the alpha 5 subunit in the adhesion plaque demonstrates a molecular difference between these two adherens junctions. It also points to possible origins of junctional specificity on muscle. Differences between these two junctions were developed further using an antibody against phosphotyrosine (PY20). Phosphotyrosine is thought to participate in the organization and stabilization of adhesions. The focal adhesion and the neuromuscular junction, but not the MTJ, contained proteins phosphorylated on tyrosine.