University of Massachusetts Amherst biologists have discovered a secret of how cells organize chromosomes to prepare for dividing. Their unexpected finding is reported in this week’s issue of the journal, Current Biology.
The experiments sought to reveal how the cell’s tiny, two-part chemical engine known as dynein, just 40 nanometers in diameter, takes charge of mitosis and keeps the delicate strands of chromosomes in order and in position. Until now, cell biologists had assumed it was the dynein’s cargo domain that regulated this process. UMass Amherst cell biologist Wei-lih Lee and colleagues showed that it is the motor domain instead.
Dynein, like a delivery truck, carries cargo, Lee explains, but this protein truck is specialized because it interacts chemically and physically with the road. In the cell, this means dynein travels along segments of polymeric microtubule “roads” that grow and shrink as needed by adding or dropping sections. From experiments in budding yeast, Lee, with a talented postdoctoral fellow, Steven Markus, and biology junior fellow Jesse Punch, found that “dynein has a preference for locating at the ends of these microtubule tracks.”
Lee says a lot of credit for a cleverly designed and executed set of experiments goes to Markus, who cut the dynein engines into motor and cargo halves and challenged the yeast cells to divide with access to only one part of the protein at a time. Markus also designed brighter-than-usual fluorescent probes to attach to the two dynein parts, red for the engine, green for the cargo domain. The strategies worked. The UMass Amherst research team now has one of the most elegant and practical probes for studying dynein function. Lee says, “I’m already getting requests from other researchers who want to use our new probes.”
In this system, they observed that like a moving walkway at the airport, “dynein is a smart truck because it parks at the end of the microtubule, and ‘rides’ along as the track grows,” Lee explains. “Our findings show that the dynein’s motor domain, the engine’s core, is responsible for this end-binding property, which is surprising given that the same domain is used for walking along the track.”
Applying their new understanding to cell division, the researchers say, “our findings further suggest that the dynein engine is turned off when it is parked on the microtubule end, but then turned on upon reaching the proper attachment site in the daughter cell’s wall,” says Lee. “This mechanism allows the yeast cell to control dynein activation with high accuracy” and avoids potential problems of transporting an “activated” protein through the cell.
Results of this new knowledge in basic science are also relevant for human nerve cell function. “It has already been shown that nerve cells use the same mechanism as yeast does to move the cell body,” says Lee. Dynein malfunction can lead to mistakes in nerve cell migration which causes poor brain development disease such as lissencephaly.
This work was supported by National Institute of General Medical Sciences, the Marine Biological Laboratory, and the Biology Department HHMI Undergraduate Science Program.
Wei-lih Lee | Newswise Science News
North and South Cooperation to Combat Tuberculosis
22.03.2018 | Universität Zürich
Researchers Discover New Anti-Cancer Protein
22.03.2018 | Universität Basel
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
22.03.2018 | Trade Fair News
22.03.2018 | Earth Sciences
22.03.2018 | Earth Sciences