Majewski Łukasz, Sobczak Magdalena, Redowicz Maria Jolanta
Department of Biochemistry, Nencki Institute of Experimental Biology, Warszawa, Poland.
Acta Biochim Pol. 2010;57(1):109-14. Epub 2010 Mar 2.
Myosin VI (MVI) is the only known myosin walking towards minus end of actin filaments. Here, MVI, but not myosins IB or IIB, was detected in chromaffin granules isolated from bovine medulla and found to be tightly associated with the granule apical surface. MVI also localized to secretory granules within rat pheochromocytoma PC12 cells as well as to the Golgi apparatus, endoplasmic reticulum and clathrin-coated pits. Notably, it was also found in the nucleus. RT-PCR revealed that MVI splice variants with a large insert (LI), characteristic of polarized cells, were barely detectable in PC12 cells, whereas variants with a small insert (SI) were the major isoforms. The presented data indicate that MVI in adrenal medulla cells is engaged in secretory vesicle trafficking within the cytoplasm and possibly also involved in transport within the nucleus.
肌球蛋白VI（MVI）是已知唯一向肌动蛋白丝负极移动的肌球蛋白。在此，在从牛髓质分离的嗜铬颗粒中检测到MVI，但未检测到肌球蛋白IB或IIB，并且发现其与颗粒顶端表面紧密相关。MVI还定位于大鼠嗜铬细胞瘤PC12细胞内的分泌颗粒以及高尔基体、内质网和网格蛋白包被小窝。值得注意的是，在细胞核中也发现了它。逆转录聚合酶链反应（RT-PCR）显示，具有大插入片段（LI）、为极化细胞所特有的MVI剪接变体在PC12细胞中几乎检测不到，而具有小插入片段（SI）的变体是主要的同工型。所呈现的数据表明，肾上腺髓质细胞中的MVI参与细胞质内分泌囊泡的运输，并且可能也参与细胞核内的运输。
