Comparison of the small heat shock proteins αB-crystallin, MKBP, HSP25, HSP20, and cvHSP in heart and skeletal muscle
Comparison of the small heat shock proteins αB-crystallin, MKBP, HSP25, HSP20, and cvHSP in heart and skeletal muscle
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DOI：
10.1007/s00418-004-0711-z
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发表时间：
2004-11-01
影响因子：
2.3
通讯作者：
Drenckhahn, D
中科院分区：
文献类型：
--
作者：
Golenhofen, N;Perng, MD;Drenckhahn, D
小热休克蛋白（sHSP）家族的七个成员在肌肉组织中的组成性高丰度方面是例外的。有研究表明，sHSPs具有分子伴侣的特性，可以在应激条件下稳定肌原纤维蛋白，防止其功能丧失。在本研究中，5 sHSP（α B-晶体蛋白，MKBP，HSP 25，HSP 20，和cvHSP）进行了研究，在正常和缺血条件下，他们在心脏和骨骼肌表达的相似性和差异。在缺血心脏和骨骼肌中，这五种sHSP从胞质移位到肌原纤维的Z-/I-区。所有sHSP的肌原纤维结合是非常紧密的，并且抵抗用1 M NaSCN或1 M尿素的大部分提取。MKBP和HSP 20被1 M NaSCN提取到显著的程度，表明这两种sHSP可能部分结合到通过该处理完全提取的肌动蛋白相关蛋白。超微结构定位的alphaB-晶体蛋白显示弥漫性分布的免疫金标记在整个I-带骨骼肌纤维，而在心肌细胞alphaB-晶体蛋白优先位于N-线位置的I-带。这些观察结果表明不同的肌原纤维结合位点的α B-晶体蛋白在心肌细胞与骨骼肌纤维。sHSPs的纤维类型分布可以观察到sHSPs性质的进一步差异。因此sHSPs在横纹肌组织中形成了一个复杂的应激反应系统，在不同的肌肉类型中既有一些共同的功能，也有一些不同的功能。
Seven members of the small heat shock protein ( sHSP) family are exceptional with respect to their constitutive high abundance in muscle tissue. It has been suggested that sHSPs displaying chaperone-like properties may stabilize myofibrillar proteins during stress conditions and prevent them from loss of function. In the present study five sHSPs (alphaB-crystallin, MKBP, HSP25, HSP20, and cvHSP) were investigated with respect to similarities and differences of their expression in heart and skeletal muscle under normal and ischemic conditions. In ischemic heart and skeletal muscle these five sHSPs translocated from cytosol to the Z-/I-area of myofibrils. Myofibrillar binding of all sHSPs was very tight and resisted for the most part extraction with 1 M NaSCN or 1 M urea. MKBP and HSP20 became extracted by 1 M NaSCN to a significant extent indicating that these two sHSPs may bind partially to actin-associated proteins which were completely extracted by this treatment. Ultrastructural localization of alphaB-crystallin showed diffuse distribution of immunogold label throughout the entire I-band in skeletal muscle fibers whereas in cardiomyocytes alphaB-crystallin was preferentially located at the N-line position of the I-band. These observations indicate different myofibrillar binding sites of alphaB-crystallin in cardiomyocytes versus skeletal muscle fibers. Further differences of the properties of sHSPs could be observed regarding fiber type distribution of sHSPs. Thus sHSPs form a complex stress - response system in striated muscle tissue with some common as well as some distinct functions in different muscle types.