Neonatal rat cardiomyocytes possess a large population of stable microtubules that is enriched in post-translationally modified subunits.
Neonatal rat cardiomyocytes possess a large population of stable microtubules that is enriched in post-translationally modified subunits.
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新生大鼠心肌细胞拥有大量稳定的微管，这些微管富含翻译后修饰的亚基。
DOI：
10.1006/jmcc.1997.0517
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发表时间：
1997
影响因子：
5
通讯作者：
D. Webster
中科院分区：
文献类型：
--
作者：
D. Webster
微管（MTs）可能参与多种分化特异性心肌细胞功能，包括肌原纤维组织、肥厚细胞生长和心脏细胞收缩的负性调节。分析了新生大鼠心脏细胞mt的功能特征，这些mt具有富含去酪氨酸或乙酰化小管蛋白亚基的亚群。与非心肌细胞相比，心肌细胞MTs对高浓度（33微米）nocodazole（超过10-30分钟），冷处理（10分钟至8小时）或钙（50-100微米，使用洗涤剂提取的细胞）具有更强的抵抗力。这些稳定MT与改良MT群体相关。10微米紫杉醇处理4小时的肌细胞显示出修饰微管蛋白水平升高，但只有中度MT捆绑或重排，而在过夜处理后，其强度和分布发生了显著变化。相比之下，相同覆盖层上的非肌细胞显示出更大的MT重排，但修饰后的MT免疫染色强度仅适度增加。最后，将半抗原标记的微管蛋白微注射到肌细胞中，其掺入率与本研究中非肌细胞的掺入率以及其他研究中确定的成纤维细胞率相似，这表明心肌细胞中修饰的MT可能只是适度稳定。因此，新生儿心肌细胞中的一个重要的MTs亚群在翻译后被修饰，对各种药物的解聚具有抗性，但仍在翻动。这些mt可能有助于确定心肌细胞在心脏发育过程中的功能。
Microtubules (MTs) may be involved in several differentiation-specific cardiomyocyte functions, including myofibril organization, hypertrophic cell growth, and the negative regulation of heart cell contraction. The functional characteristics of neonatal rat heart cell MTs, which possess subsets that are enriched with either detyrosinated or acetylated tubulin subunits, were analysed. When compared with their non-myocyte neighbors, cardiomyocyte MTs were found to be more resistant to high concentrations (33 microM) of nocodazole (over 10-30 min), cold treatments (10 min to 8 h), or calcium (50-100 microM for 1-10 min, using detergent-extracted cells). These stable MTs were correlated with the modified MT population. Myocytes treated with 10 microM taxol for 4 h showed elevated levels of modified tubulin but only moderate MT bundling or rearrangement, while after an overnight treatment significant changes in intensity and distribution were noted. In contrast, non-myocytes on the same coverslip showed much greater MT rearrangements, but with only a moderate increase in the immunostaining intensity for modified MTs. Finally, hapten-labeled tubulin that was microinjected into the myocytes showed incorporation rates that were similar to those of the non-myocytes in this study as well as to fibroblast rates determined in other studies, suggesting that the modified MTs in cardiomyocytes may be only moderately stable. Thus, a significant subset of MTs in neonatal cardiomyocytes are post-translationally modified, are resistant to depolymerization by a variety of agents, but are still turning over. These MTs may help define myocyte function during heart development.