Salvatori S, Biral D, Furlan S, Marin O
Centro di Studio per la Biologia e la Fisiopatologia Muscolare del Consiglio Nazionale delle Ricerche, Dipartimento di Scienze Biomediche Sperimentali, University of Padova, Italy.
J Muscle Res Cell Motil. 1997 Aug;18(4):429-40. doi: 10.1023/a:1018694730773.
Myotonic dystrophy is an autosomal dominant multisystem disease primarily affecting skeletal muscle and is characterized by the presence of an amplified trinucleotide repeat in the 3' untranslated region of the myotonic dystrophy protein kinase gene. In this study, the subcellular localization of the myotonic dystrophy protein kinase in muscle tissues has been investigated at both morphological and biochemical level, by using antibodies against the myotonic dystrophy protein kinase. Immunofluorescence studies and Western-blot analysis were carried out with antibodies raised against both a synthetic peptide and a recombinant fusion protein fragment specific for the myotonic dystrophy protein kinase. The kinase is localized both to the surface membranes, and within the skeletal fibres in the region of the A-I band boundary. Consistent with the A-I location of the kinase is that Western-blot analysis of purified fractions from sarcoplasmic reticulum show that triads and sarcoplasmic reticulum terminal cisternae are immunoreactive for two myotonic dystrophy protein kinase proteins of different molecular weight (85 and 54 kDa). The relative amount of these two proteins is different in relation to the muscle type, the 85 kDa protein being more evident in skeletal than in cardiac fibres. In addition, immunofluorescence studies of cardiac muscle reveal a heavy concentration of DM-PK localized to the intercalated discs, as well as a weaker reaction in the sarcoplasm. These results taken together suggest that multiple isoforms of the DM-PK may exist and that they may be differentially located in muscle tissues.
强直性肌营养不良是一种常染色体显性多系统疾病，主要影响骨骼肌，其特征是在强直性肌营养不良蛋白激酶基因的3'非翻译区存在三核苷酸重复序列扩增。在本研究中，通过使用抗强直性肌营养不良蛋白激酶的抗体，在形态学和生物化学水平上研究了强直性肌营养不良蛋白激酶在肌肉组织中的亚细胞定位。使用针对强直性肌营养不良蛋白激酶特异性的合成肽和重组融合蛋白片段产生的抗体进行了免疫荧光研究和蛋白质印迹分析。该激酶定位于表面膜以及A-I带边界区域的骨骼肌纤维内。与激酶在A-I带的定位一致的是，对肌浆网纯化组分进行蛋白质印迹分析表明，三联体和肌浆网终池对两种不同分子量（85和54 kDa）的强直性肌营养不良蛋白激酶蛋白具有免疫反应性。这两种蛋白的相对含量因肌肉类型而异，85 kDa蛋白在骨骼肌中比在心肌纤维中更明显。此外，对心肌的免疫荧光研究显示，DM-PK大量集中在闰盘，肌浆中的反应较弱。综合这些结果表明，DM-PK可能存在多种同工型，并且它们可能在肌肉组织中定位不同。
