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【bio-news】分子马达与分子刹车在细胞中一起发挥
01/30/07 -- Researchers at the University of Pennsylvania School of Medicine have discovered that microtubules - components responsible for shape, movement, and replication within cells - use proteins that act as molecular motors and brakes to organize into their correct structure. If microtubules are not formed properly such basic functions as cell division and transport can go wrong, which may have implications in such disease processes as cancer and dementia. The study, published in the January issue of Cell, is featured on the cover of that issue.
"Up until now motors and brakes were studied separately from microtubules," says senior author Phong Tran, PhD, Assistant Professor of Cell and Developmental Biology. "This study lets us have a more complete picture."
Microtubules are structures that help give shape to many types of cells, form the spindle - a structure important in cell division - and act as a railroad, of sorts, upon which molecular motors move protein packages for waste removal and nerve transmission.
In the Cell study, the investigators, working with fission yeast cells, showed that stable end-to-end arrays of microtubules can be achieved by a balance between the sliding by a molecular motor called klp2p and the braking of a microtubule-associated protein (MAP) called ase1p. Specifically, they showed that a preexisting "mother" microtubule acts as a platform on which a new microtubule can be formed. The new "daughter" microtubule grows and moves along the mother microtubule. In time, the daughter grows beyond the end of the mother to ultimately produce two microtubules, connected by the cross-linking MAP ase1p.
"Imagine that the daughter microtubule is a short train on the track of the mother microtubule," explains Tran. "The molecular motor is the train's engine, but the problem is that the cargo - the molecular brakes - gets longer, slowing down the daughter train. But when the train gets to the end of the track it remains attached to the end of mother microtubule. At the tail end, it stops moving and that defines the region of overlap. Our work shows that the cell can make microtubule structures of defined lengths stable by coordinating the sliding of the motors and the slowing of the brakes."
If microtubule-based structures are not formed properly because of failures in brakes or motors, such basic functions as cell division and cell transport can go awry, with such diseases as cancer and dementia possibly resulting. "For the first time we have shown how MAPs and motors work together in a mechanistic way," says Tran. "This is important and it will make other people who study microtubules rethink how they study the cell."
Co-authors are Marcel E. Jansen, Isabelle Loïodice, and Chuanhai Fu, all from Penn, and Rose Loughlin, Damian Brunner, and Fran?ois J. Nédélec from the European Molecular Biology Laboratory, Heidelberg, Germany. The research was sponsored by the National Institutes of Health.
Source: University of Pennsylvania School of Medicine
http://www.bio.com/newsfeatures/newsfeatures_research.jhtml;jsessionid=Q5BGMLYAOLKXNR3FQLMSFEWHUWBNQIV0?cid=25800025 本人已认领该文编译，48小时后若未提交译文，请其他战友自由认领。
分子马达与分子刹车在细胞中一起发挥作用
Researchers at the University of Pennsylvania School of Medicine have discovered that microtubules - components responsible for shape, movement, and replication within cells - use proteins that act as molecular motors and brakes to organize into their correct structure. If microtubules are not formed properly such basic functions as cell division and transport can go wrong, which may have implications in such disease processes as cancer and dementia. The study, published in the January issue of Cell, is featured on the cover of that issue.
宾夕法尼亚大学医学院的研究人员发现，微管（对于细胞成形、运动和复制起重要作用的部分）能够利用那些起到分子马达和刹车作用的蛋白质组成合理结构。如果微管没有正确的形成将会导致象细胞分裂和运输一样的基本功能不能正常实现，这可能暗示象癌症和痴呆一样的疾病进程。这项研究发表在1月的《细胞》杂志的封面上。
"Up until now motors and brakes were studied separately from microtubules," says senior author Phong Tran, PhD, Assistant Professor of Cell and Developmental Biology. "This study lets us have a more complete picture."
据本文资深作者、细胞和发育生物学助理教授Phong Tran博士介绍，“在此之前，对微管中分子马达和分子刹车的研究一直是分开的。” “这项研究让我们有了全新认识。”
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作者:admin@医学,生命科学 2011-02-20 05:11
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