U.S.-Czech Cell Biology Research on Nuclear Myosin I

这个由芝加哥伊利诺伊大学的Primal de Lanerolle和布拉格实验医学研究所的Pavel Hozak合作的美国-捷克研究项目将试图通过克隆和测序其cDNA来鉴定一种非丝状运动蛋白myosin I。他们的目的是通过使用免疫金电子显微镜来确定这种蛋白质在细胞核中的相关结构，从而开始定义这种蛋白质的生理功能。测序结果将与已公布的肌凝蛋白超家族成员的序列进行比较，以确定120 kDa蛋白是肌凝蛋白I，还是其他一些非常规的肌凝蛋白，还是细胞核中全新的肌动蛋白，ATP和钙调蛋白结合的ATP酶。这项工作的核心是一种针对肌球蛋白I的抗体，美国和捷克的研究人员已经生产出这种抗体，并从牛肾上腺中亲和纯化出来。该抗体抑制纯化的肾上腺肌球蛋白I的肌动蛋白激活的atp酶活性，而不抑制纯化的肾上腺肌球蛋白II的atp酶活性。这些抗体识别细胞质和细胞核中大于抗原（16 kDa）的120 kDa蛋白。使用不同的肌球蛋白I抗体的比较研究表明，这些抗体识别一种独特的，以前未描述过的肌球蛋白I异构体，这是一种核内肌动蛋白为基础的分子马达。如果成功，这项明确鉴定120 kDa蛋白的研究将为我们理解肌球蛋白的细胞功能和细胞核生物学做出基础贡献。这个细胞组织的项目实现了推进科学知识的计划目标，使美国和中欧的领先专家能够在共同感兴趣和能力强的领域结合互补的人才和汇集资源。？?

INT 9724168 de Lanerolle This U.S.-Czech research project between Primal de Lanerolle of the University of Illinois, Chicago, and Pavel Hozak of the Institute of Experimental Medicine, Prague, will attempt to identify a non-filamentous motor protein, myosin I, by cloning and sequencing the cDNA for it. Their intent is to initiate the process of defining the physiological functions of this protein by using immunogold electron microscopy to identify the structures it associates with in the nucleus. Results of the sequencing will be compared to published sequences for members of the myosin superfamily to determine whether the 120 kDa protein is myosin I, some other unconventional myosin, or a totally new actin, ATP and calmodulin binding ATPase in the nucleus. Central to the effort is an antibody to myosin I, which the U.S. and Czech researchers have produced and affinity purified from bovine adrenal glands. This antibody inhibits the actin-activated ATPase activity of purified adrenal myosin I but not that of purified adrenal myosin II. These antibodies recognize a 120 kDa protein that is larger than the antigen (16 kDa) in the cytoplasm and in the nucleus. Comparative studies using different antibodies to myosin I suggest that these antibodies recognize a unique, previously undescribed myosin I isoform that is an intranuclear actin-based molecular motor. If successful, this research effort to unequivocally identify the 120 kDa protein could make fundamental contributions to our understanding of the cellular functions of myosin and the biology of the cell nucleus. This project in cellular organization fulfills the program objective of advancing scientific knowledge by enabling leading experts in the United States and Central Europe to combine complementary talents and pool resources in areas of strong mutual interest and competence. ??