期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1978
卷号：75
期号：4
页码：1867-1871
DOI：10.1073/pnas.75.4.1867
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Calcium-dependent regulator protein is a low molecular weight (17,000), thermostable, calcium binding protein which is structurally homologous to skeletal muscle troponin C. This protein is present in all nonmuscle cells and has been shown to decorate stress fibers in interphase cells by indirect immunofluorescence. Using this procedure we have investigated the distribution of the protein during mitosis of eukaryotic cells. As the cells enter prophase, the distinct cytoplasmic localization disappears commensurate with the dissolution of the cytoskeleton. The regulator protein seems to be randomly distributed throughout the prophase cell, including the region around the condensed chromosomes. However, at prometaphase, it is localized in association with the half-spindles of the mitotic apparatus. Through metaphase and most of anaphase, the protein remains localized between the chromosomes and the poles of the spindle. During late anaphase the protein is also found in the interzone region but rapidly condenses into two small regions, one on each side of the midbody that separates the daughter cells. The regulator protein is not localized in the cleavage furrow during telophase, whereas actin is demonstrable in this region. Indeed, placement of the protein during mitosis is distinct from both that of actin and that of tubulin. The localization of calcium-dependent regulator protein during mitosis suggests that it may mediate the calcium effects on the mitotic apparatus and thus play a role in chromosome movement.
关键词：calcium binding protein ; mitosis ; microfilaments ; microtubules
