 |
|
How an enzyme tells stem cells which way to divide
May 14, 2009Driving Miranda, a protein in fruit flies crucial to switch a stem cell's fate, is not as complex as biologists thought, according to University of Oregon biochemists. They've found that one enzyme (aPKC) stands alone and acts as a traffic cop that directs which roads daughter cells will take.
"Wherever aPKC is at on a cell's cortex or membrane, Miranda isn't," says Kenneth E. Prehoda, a professor in the chemistry department and member of the UO's Institute of Molecular Biology. When a stem cell duplicates into daughter cells, the side, or cortical domain, containing aPKC (atypical protein kinase C) continues as a stem cell, while the other domain with Miranda becomes a differentiated cell such as a neuron that forms the central nervous system.
Prehoda and co-author Scott X. Atwood, who studied in Prehoda's lab and recently earned his doctorate, describe how the mechanism works in the May 12 issue of the journal Current Biology.
Instead of a complex cascade of protein deactivation steps that many biologists have theorized, Prehoda said, aPKC strips phosphate off an energy-transfer nucleotide known as ATP and then attaches it to Miranda. This process forces Miranda away from aPKC and helps determine the fates of subsequent daughter cells.
"This process is pretty simple," he said, when viewed from a biochemical perspective. "What happens is that Miranda gets phosphorylated by aPKC, turning it into an inactivated substrate and pushing it into another location in the cell."
Much of the paper in Current Biology is devoted to why the more complex scenarios are not accurate. "There have been a lot of ideas on how this works, and most seemed to be really complicated and difficult to explain. We have found it's a much simpler mechanism," Prehoda said, adding that the mechanism likely is similar in many other types of cells, not just stem cells.
"It's a basic-research question. How does this polarity occur? In order to develop stem cell-specific therapeutics based on a rational methodology you have to understand the mechanism," he said.
If Miranda is improperly isolated into other regions by aPKC, the stem cell divides symmetrically, with both daughter cells adopting the same fate, In turn, Prehoda said, these cells can become tumorous as they continue to rapidly divide without proper polarization.
University of Oregon
Instead of a complex cascade of protein deactivation steps that many biologists have theorized, Prehoda said, aPKC strips phosphate off an energy-transfer nucleotide known as ATP and then attaches it to Miranda. This process forces Miranda away from aPKC and helps determine the fates of subsequent daughter cells.
"This process is pretty simple," he said, when viewed from a biochemical perspective. "What happens is that Miranda gets phosphorylated by aPKC, turning it into an inactivated substrate and pushing it into another location in the cell."
Much of the paper in Current Biology is devoted to why the more complex scenarios are not accurate. "There have been a lot of ideas on how this works, and most seemed to be really complicated and difficult to explain. We have found it's a much simpler mechanism," Prehoda said, adding that the mechanism likely is similar in many other types of cells, not just stem cells.
"It's a basic-research question. How does this polarity occur? In order to develop stem cell-specific therapeutics based on a rational methodology you have to understand the mechanism," he said.
If Miranda is improperly isolated into other regions by aPKC, the stem cell divides symmetrically, with both daughter cells adopting the same fate, In turn, Prehoda said, these cells can become tumorous as they continue to rapidly divide without proper polarization.
University of Oregon
Stem Cell Current Events and Stem Cell News RSSFirst reconstitution of an epidermis from human embryonic stem cells
Stem cell research is making great strides. This is yet again illustrated by a study carried out by the I-STEM* Institute (I-STEM/ Inserm UEVE U861/AFM), published in the Lancet on 21 November 2009. The I-STEM team, directed by Marc Peschanski has just succeeded in recreating a whole epidermis from human embryonic stem cells.
Your Own Stem Cells Can Treat Heart Disease
The largest national stem cell study for heart disease showed the first evidence that transplanting a potent form of adult stem cells into the heart muscle of subjects with severe angina results in less pain and an improved ability to walk. The transplant subjects also experienced fewer deaths than those who didn't receive stem cells.
U of M researchers find 2 units of umbilical cord blood reduce risk of leukemia recurrence
A new study from the Masonic Cancer Center, University of Minnesota shows that patients who have acute leukemia and are transplanted with two units of umbilical cord blood (UCB) have significantly reduced risk of the disease returning.
Researchers find potential treatment for Huntington's disease
Investigators at Burnham Institute for Medical Research (Burnham), the University of British Columbia's Centre for Molecular Medicine and Therapeutics and the University of California, San Diego have found that normal synaptic activity in nerve cells (the electrical activity in the brain that allows nerve cells to communicate with one another) protects the brain from the misfolded proteins associated with Huntington's disease.
Researchers 'notch' a victory toward new kind of cancer drug
Scientists have devised an innovative way to disarm a key protein considered to be "undruggable," meaning that all previous efforts to develop a drug against it have failed.
UCI embryonic stem cell therapy restores walking ability in rats with neck injuries
The first human embryonic stem cell treatment approved by the FDA for human testing has been shown to restore limb function in rats with neck spinal cord injuries - a finding that could expand the clinical trial to include people with cervical damage.
First use of antibody and stem cell transplantation to successfully treat advanced leukemia
For the first time, researchers at Fred Hutchinson Cancer Research Center have reported the use of a radiolabeled antibody to deliver targeted doses of radiation, followed by a stem cell transplant, to successfully treat a group of leukemia and pre-leukemia patients for whom there previously had been no other curative treatment options.
Immune therapy can protect against or treat later lymphoma
Specially developed immune system cells that target the common Epstein-Barr virus can protect immune-suppressed bone marrow transplant recipients against lymph system disease and cancers that arise from the viral infection.
Immunotherapy demonstrates long-term success in treating lymphoma
Targeted immunotherapy has been an attractive new therapeutic area for a number of cancers because it has the potential to destroy tumor cells without damaging surrounding normal tissue. New study results demonstrate high success rates using specialized white blood cells to prevent or treat lymphoma associated with the Epstein-Barr virus (EBV-lymphoma) in patients who have received a hematopoietic stem cell transplant (HSCT).
Of mice and men: Stem cells and ethical uncertainties
The recent creation of live mice from induced pluripotent stem cells (iPSCs) not only represents a remarkable scientific achievement, but also raises important issues, according to bioethicists at The Johns Hopkins University's Berman Institute of Bioethics.
More Stem Cell Current Events and Stem Cell News Articles
 |
Essentials of Stem Cell Biology, Second Edition by Robert Lanza (Editor), John Gearhart (Editor), Brigid Hogan (Editor), Douglas Melton (Editor), Roger Pederson (Editor), E. Donnall Thomas (Editor), James Thomson (Editor), Sir Ian Wilmut (Editor) First developed as an accessible abridgement of the successful Handbook of Stem Cells, Essentials of Stem Cell Biology serves the needs of the evolving population of scientists, researchers, practitioners and students that are embracing the latest advances in stem cells. Representing the combined effort of seven editors and more than 200 scholars and scientists whose pioneering work has defined our understanding of stem cells, this book combines the prerequisites for a general understanding of adult and embryonic stem cells with a presentation by the world?s experts of the latest research information about specific organ systems. From basic biology/mechanisms, early development, ectoderm, mesoderm, endoderm, methods to application of stem cells to specific human diseases, regulation and... |
 |
Stem Cell Now by Christopher Thomas Scott (Author) The essential account of the most important scientific advance—and most volatile ethical debate—of our time While many believe stem cell research holds the key to curing a wide range of ailments, others see this research as opening a Pandora’s box that will devalue human life. In Stem Cell Now, Christopher Scott—executive director of Stanford University’s Stem Cells and Society Program—lays out the scientific and ethical issues surrounding this national dilemma. Scott guides readers through the latest advances in stem cell research in clear, accessible language, telling the stories of the researchers who are exploring the potential of stem cells to cure cancer, grow new organs, and repair the immune system. He also leads readers through a... |
 |
The Stem Cell Divide: The Facts, the Fiction, and the Fear Driving the Greatest Scientific, Political, and Religious Debate of Our Time by Michael Bellomo (Author) There has been much recent debate about the merits, dangers, and nature of stem cell research. Some see in it the answer to every debilitating disease known to man, while others see it as a step away from human cloning. While the battle has raged, research is moving ahead, and California has already passed a measure that will give $3 billion in support to stem cell research. But as politics, religion, and the media weigh in on this complex issue, more and more of the scientific reality of stem cell research is getting lost. In the search for the truth about stem cell science, the author has interviewed the scientists whose cutting-edge research is at the very heart of this hot-button issue. The book explains what they have accomplished so far, what they're currently doing, and what... |
 |
Human Stem Cell Manual: A Laboratory Guide by Jeanne F. Loring (Editor), Robin L. Wesselschmidt (Editor), Philip H. Schwartz (Editor) Stem cells are self-replicating and undifferentiated, meaning their function is not yet cell, tissue, or organ-specific. Due to the unique nature of these cells, research into their biology and function holds great promise for therapeutic applications through replacement or repair of diseased and damaged cells. This reader-friendly manual provides a practical "hands on" guide to the culture of human embryonic and somatic stem cells. By presenting methods for embryonic and adult lines side-by-side, the authors lay out an elegant and unique path to understanding the science of stem cell practice. The authors begin with a broad-based introduction to the field, and also review legal and regulatory issues and patents. Each experimental strategy is presented with an historical introduction,... |
 |
Stem Cell Research: Medical Applications And Ethical Controversy (The New Biology) by Joseph, Ph.D. Panno (Author) This is an informative reference to the technological advances, applications, and issues of stem cell research. The past few years have seen controversy and debate surrounding stem cell research. Because skin cells have the capability to divide - unlike most of the cells in our body - our skin can heal itself through the division of cells. Scientists have attempted to apply this concept to major organs, trying to see if stem cells can be used to make the repairs that post-mitotic cells cannot. "Stem Cell Research" is a comprehensive and interesting introduction to this popular new science for non-experts. Explaining how stems cells can be obtained from several places, including skin, bone marrow, and most usefully, embryos, this book covers all the fundamental aspects of stem cell... |
 |
Cell of Cells: The Global Race to Capture and Control the Stem Cell by Cynthia Fox (Author) Publication Date is March 26, 2007 |
 |
Stem Cell Medicine: The New Adult Stem Cell Regenerative Therapy for Cancer, Spinal Injuries, Multiple Sclerosis, Parkinson's and other conditions. by Robin Smith MD MBA (Author), Suzanne Somers (Foreword) Unlock the Power of Your Own Cells Stem Cell Medicine gives an authoritive, comprehensive and understandable "crash course" in this important scientific technology, and explains how the adult stem cell--extracted from patients' own bodies--offers incredible curative possibilities, without political controversy. As a primitive cell that call transform into many different types of cells, the adult stem cell can be used to combat a variety of diseases, including multiple sclerosis, heart disease, cancer, leukemia and Lupus. Real-life sucess stories prove that this technology that seems "too good to be true" is actually changing lives. In addition to presenting remarkable evidence and true stories of stem cells treating and, in many cases, curing diseases, Stem Cell... |
 |
The Stem Cell Dilemma: Beacons of Hope or Harbingers of Doom? by Leo Furcht (Author), William Hoffman (Author) TodayÕs scientists are showing us how stem cells create and repair the human body. Unlocking these secrets has become the new Holy Grail of biomedical research. But behind that search lies a sharp divide. Stem cells offer the hope of creating or repairing tissues lost to age, disease, and injury. Yet because of this ability, stem cells hold the potential to incite an international biological arms race. THE STEM CELL DILEMMA will tell you everything you ever wanted to know about stem cells: what they are, how they work, and why their use has become so controversial. We are standing at a scientific crossroads, the likes of which the world has never seen. It is a moment that will change forever the practice of medicine and the future of life as we know it. |
 |
Mesenchymal Stem Cells: Methods and Protocols (Methods in Molecular Biology) by Darwin J. Prockop (Editor), Donald G. Phinney (Editor), Bruce A. Bunnell (Editor) For over forty years, mesenchymal stem cells (MSCs) have been scrutinized and studied, garnering much attention due to their broad therapeutic efficacy. In Mesenchymal Stem Cells: Methods and Protocols, leaders in the field were assembled to contribute detailed methodologies for the isolation and characterization of human and rodent MSCs. Recently, these vital cells have shown therapeutic benefits in the treatment of myocardial infarction, stroke, lung diseases, spinal cord injury and other neurological disorders, thus promising a boundless future in their study. Cutting edge and easy to use, Mesenchymal Stem Cells: Methods and Protocols is the perfect resource for scientists attempting to pursue this important and ever-developing field of research. |
 |
Essential Stem Cell Methods (Reliable Lab Solutions) by Robert Lanza (Editor), Irina Klimanskaya (Editor) As part of the Reliable Lab Solutions series, this volume offers an abridged and comprehensive update of selected chapters that first appeared in the three-volume stem cell series published in Methods in Enzymology. Currently, stem cells are of great interest to scientists and clinicians due to their unique ability to differentiate into various tissues of the body, making them a promising source of cells for regenerative medicine and drug discovery as well as an excellent model of vertebrate development. Essential Stem Cell Methods features a detailed set of protocols written by experts in the field and hand-selected by the editors to help researchers drive advances in this fast-moving field. The result is a clear set of step-by-step methods which steer the reader... |
| © 2009 BrightSurf.com |