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From mother to daughters: A central mystery in cell division solved
December 09, 2008Researchers from the Ludwig Institute for Cancer Research at the University of California, San Diego School of Medicine have identified a key step required for cell division in a study that could help improve therapies to treat cancer. Their work describing the mechanism of the contractile ring - a structure that pinches the mother cell into two daughter cells - has been published in the December 5 issue of the journal Science.
The division of one cell into two is accomplished by the contractile ring, which is assembled from two protein filament types, actin and myosin, that are also used in muscle. During cell division, the genome is replicated and the two copies are separated to opposite sides of the cell by the mitotic spindle. The spindle then directs the assembly of a contractile ring, which forms a belt around the cell middle.
As happens during muscle contraction, the myosin filaments move along the actin filaments and constrict the ring. Constriction "tightens the belt," pinching the mother cell into two daughter cells.
"Normally, the contractile ring is built from long, straight actin filaments, which serve as tracks on which myosin filaments move along to drive constriction," said Karen Oegema, Ph.D, assistant professor at the Ludwig Institute and the Department of Cellular and Molecular Medicine at UC San Diego School of Medicine. "We discovered that a key step in ring constriction is turning off a pathway that would form branches on these long filaments, preventing them from being efficient tracks for myosin filament movement."
"This discovery will open the door to further studies of cell division that could improve chemotherapies for cancer," said first author Julie Canman, Ph.D., postdoctoral fellow in the areas of leukemia and lymphoma at UC San Diego and the Ludwig Institute. "Right now, drugs used in chemotherapy affect the division of all the body's cells, leading to adverse side effects, like sterility and death of the white blood cells that are essential for immunity," said Canman. "If we could specifically target the dividing cancer cells, we could improve on current chemotherapy to treat cancer with fewer side effects, allowing patients to continue therapy with a higher quality of life."
University of California - San Diego
"Normally, the contractile ring is built from long, straight actin filaments, which serve as tracks on which myosin filaments move along to drive constriction," said Karen Oegema, Ph.D, assistant professor at the Ludwig Institute and the Department of Cellular and Molecular Medicine at UC San Diego School of Medicine. "We discovered that a key step in ring constriction is turning off a pathway that would form branches on these long filaments, preventing them from being efficient tracks for myosin filament movement."
"This discovery will open the door to further studies of cell division that could improve chemotherapies for cancer," said first author Julie Canman, Ph.D., postdoctoral fellow in the areas of leukemia and lymphoma at UC San Diego and the Ludwig Institute. "Right now, drugs used in chemotherapy affect the division of all the body's cells, leading to adverse side effects, like sterility and death of the white blood cells that are essential for immunity," said Canman. "If we could specifically target the dividing cancer cells, we could improve on current chemotherapy to treat cancer with fewer side effects, allowing patients to continue therapy with a higher quality of life."
University of California - San Diego
Myosin Current Events and Myosin News RSSSmall mechanical forces have big impact on embryonic stem cells
Applying a small mechanical force to embryonic stem cells could be a new way of coaxing them into a specific direction of differentiation, researchers at the University of Illinois report. Applications for force-directed cell differentiation include therapeutic cloning and regenerative medicine.
Dividing cells 'feel' their way out of warp
Every moment, millions of a body's cells flawlessly divvy up their genes and pinch perfectly in half to form two identical progeny for the replenishment of tissues and organs - even as they collide, get stuck, and squeeze through infinitesimally small spaces that distort their shapes.
St. Jude scientists discover a new mechanism controlling neuronal migration
The molecular machinery that helps brain cells migrate to their correct place in the developing brain has been identified by scientists at St. Jude Children's Research Hospital.
Intestinal cells surprisingly active in pursuit of nutrition and defense
Every cell lining the small intestine bristles with thousands of tightly packed microvilli that project into the gut lumen, forming a brush border that absorbs nutrients and protects the body from intestinal bacteria.
Muscle atrophy through thick but not thin
During desperate times, such as fasting, or muscle wasting that afflicts cancer or AIDS patients, the body cannibalizes itself, atrophying and breaking down skeletal muscle proteins to liberate amino acids.
Scripps research scientists discover molecular defect involved in hearing loss
Scientists from The Scripps Research Institute have elucidated the action of a protein, harmonin, which is involved in the mechanics of hearing.
Study offers clues to beating hearing loss
Researchers at the University of Leeds have made a significant step forward in understanding the causes of some forms of deafness.
Heart regenerates after infarction -- first trials with mice
Up until today scientists assumed that the adult heart is unable to regenerate. Now, researchers and cardiologists from the Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch and the Charité - Universitätsmedizin Berlin (Germany) have been able to show that this dogma no longer holds true.
Dense tissue promotes aggressive cancers
New research may explain why breast cancer tends to be more aggressive in women with denser breast tissue. Breast cancer cells grown in dense, rigid surroundings step up their invasive activities, Vanderbilt-Ingram Cancer Center investigators report in the Sept. 9 issue of Current Biology.
Molecular motor works by detecting minute changes in force
Researchers at the University of Pennsylvania School of Medicine discovered that the activity of a specific family of nanometer-sized molecular motors called myosin-I is regulated by force. The motor puts tension on cellular springs that allow vibrations to be detected within the body.
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Myosins: A Superfamily of Molecular Motors (Proteins and Cell Regulation) by Lynne M. Coluccio (Author), Lynne M. Coluccio (Editor) This volume highlights the remarkable superfamily of molecular motors called myosins, which are involved in such diverse cellular functions as muscle contraction, intracellular transport, cell migration and cell division. In a timely compilation of chapters written by some of the leading research groups in the world that have made key discoveries in the field, the current understanding of the molecular mechanisms and biological functions of these intriguing proteins is explored. The different myosin classes are compared and contrasted in the introductory chapter, as well as chapters on myosin structure; and biochemical and kinetic properties of myosins. Subsequent chapters are devoted to single classes of myosins and provide keen insight based on studies using in vitro and in... |
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Myosin Protein - LoCarb Synergistic Protein Complex, Chocolate by MetabolicDiet Myosin Protein contains a variety of the highest quality protein powder to make use of the special characteristics of each and thus enhancing their overall effect while at the same time eliminating their relative disadvantages. Because of the gentle processes used to isolate the various proteins, the formula maintains the beneficial immune, hormonal and other effects of the undenatured whey, casein, milk (containing colostrum), egg and soy proteins. The combination of whey, casein, milk, egg and soy proteins provides an optimal amino acid array that maximizes the anabolic effects of dietary proteins. For example, while whey protein increases protein synthesis better than casein, it is not as good at preventing muscle catabolism. There is also a synergistic effect from the types and... |
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My Oh Myosin Lisa Jones Bromfield (Primary Contributor) |
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Myosins (Protein Profile) by James R. Sellers (Author) Myosin are a diverse superfamily of molecular motors for translocating actin filaments or translocating vesicles or other cargo on fixed actin filaments. There are currently fifteen distinct classes in the superfamily, and this new editions provides a complete survey. It incorporates much of the latest research, including links between mutations in myosin and human diseases. |
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Suppression of basal and cytokine induced expression of MHC, ICAM 1 and B7 markers on mouse lung epithelial cells exposed to diesel exhaust particles.(myosin ... Journal of Biochemistry and Biotechnology by Rajiv K. Saxena (Author), Wanda Williams (Author), M. Ian Gilmour (Author) This digital document is an article from American Journal of Biochemistry and Biotechnology, published by Thomson Gale on September 22, 2007. The length of the article is 3644 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser. Citation Details Title: Suppression of basal and cytokine induced expression of MHC, ICAM 1 and B7 markers on mouse lung epithelial cells exposed to diesel exhaust particles.(myosin heavy chain; intracellular adhesion molecule)(Clinical report) Author: Rajiv K. Saxena Publication: American Journal of Biochemistry and Biotechnology (Magazine/Journal) Date: September 22,... | |
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ROCK- and Myosin-Dependent Matrix Deformation Enables Protease-Independent Tumor-Cell Invasion In Vivo [A short communication from: Current Biology by J.B. Wyckoff (Author), S.E. Pinner (Author), S. Gschmeissner (Author), Condee (Author) This digital document is a journal article from Current Biology, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser. Abstract: Tumor cells invading three-dimensional matrices need to remodel the extracellular matrix (ECM) in their path. Many studies have focused on the role of extracellular proteases [1, 2]; however, cells with amoeboid or rounded morphologies are able to invade even when these enzymes are inhibited [3, 4]. Here, we describe the mechanism by which cells move through a dense ECM without proteolysis. Amoeboid tumor cells generate sufficient actomyosin force to deform collagen fibers and are able to push through the ECM. Force... |
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Myosin Light and Heavy Chain Isoforms: Endurance Training: Skeletal Muscle Plasticity, Oxidative Capacity and Regeneration Capability. MyLC and MyHC Isoforms Turnover Rate and Relative Content by Karin Alev (Author) This study investigated the differences in the relative content of MyLC and MyHC slow and fast isoforms between fast-twitch and slow-twitch skeletal muscles. In particular, it examines the effect of endurance training, an increase in the training volume on the MyLC and MyHC relative content, turnover rate and regeneration after muscle grafting.Parallel changes of MyLC and MyHC isoforms in fast-twitch and slow-twitch skeletal muscles, and in fast-twitch muscles with different oxidative potential, occuring in response to endurance training may point to functional significance of each isoform in the process of adaptation of the contractile apparatus to muscular activity. Exhaustive exercise causes destruction in contractile machinery and decreases the turnover... |
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The interaction of actin and myosin as the basic reaction in muscular contraction (Fortschritte der Zoologie) by Peter Dancker (Author) | |
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Molecular Interactions of Actin: Actin-Myosin Interaction and Actin-Based Regulation (Results and Problems in Cell Differentiation) by D.D. Thomas (Editor), C.G. dos Remedios (Editor) Volume two of a two-part text based on the Fourth Pentennial Actin Conference held at the new Sheraton Maui in Hawaii in 1997. Companion text, Volume one (Molecular Interactions of Actin: Actin Structure and Actin-Binding Proteins) was published in December 2000. |
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Nature 28 September 1989: Myosin Isozymes in Dictyostelium by International Weekly Journal Of Science (Author) |
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