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Signal Transduction Resource
 | | | | | | A brief overview | Mechanisms involved in intercellular and intracellular communication and their effects on metabolic regulation have largely formed the basis of modern cell biology. This field of biological sciences extends into several other scientific domains including biochemistry, immunobiology, molecular biology, pharmacology, and physiology. Interaction between cells, tissues, and organs is controlled by internal and external signals that either stimulate or inhibit biological processes. The mechanism by which cells recognize and respond to these signals is one of the central issues in current research in cell biology. The biological effect of hormones, neurotransmitters, and other regulatory molecules is transferred from cell membrane to the intracellular targets, such as the mitochondria, endoplasmic reticulum, and nucleus, by a mechanism known as the Signal Transduction. This transduction of information from membrane to internal targets leads to a cascade of molecular events that translate into the ultimate biological response to the affector molecule. The past decade has seen a colossal development in biochemical and molecular biological techniques that have led not only to the identification of key enzymes involved in the Signal Transduction process, but also to the development of several natural and synthetic modulators of biological processes. These tools have helped to elucidate molecular events under normal and pathological conditions. With the advent of vast information on molecular interactions that regulate cellular responses, the potential for design and development of new drugs to treat cancer, hypertension, cardiovascular complications, and other debilitating diseases has become most intriguing. | | | | | | Sequence of events in the Signaling Process - An Example | Note: This is a representative example of hundreds of pathways involved in cell signaling. Our interactive pathways offer a broader view of a variety of these pathways.
Following their release from the glandular tissue, hormones are transported to their respective target sites via the circulatory system. However, other signaling molecules might cause their action in the close proximity of their secretory sites. The following scheme outlines some of the major events leading to the ultimate biological response. Steroid hormones can readily enter the cell. Their receptors are located in the cytoplasm and on nuclear membrane. - Hormone or growth factor binds to a specific receptor.
- The receptor causes a GDP-GTP (guanosine diphosphate-guanosine triphosphate) exchange on G-protein.
- G-protein with bound GTP activates membrane bound phospholipase C.
- Active phospholipase C cleaves phosphatidyl-inositol-4,5-bisphosphate (PIP2) to form inositol triphosphate (InsP3) and diacylglycerol (DAG).
- InsP3 binds to specific receptors on the endoplasmic reticulum and releases calcium (Ca2+).
- DAG and Ca2+ activate protein kinase C (PKC).
- Phosphorylation of proteins and enzymes by PKC produces the cellular response to the hormone.
- Ca2+ also activates other Ca2+-dependent enzymes that affect the metabolic processes.
| | | | | | | | Who are the researchers and why are they studying Signal Transduction? | | | - Diabetes and other metabolic disorders
To elucidate the mechanism of binding and action of insulin and identify the causative factors in the development of diabetes. Also, identify the intracellular sites of insulin action.
- Cancer
To identify how and why certain cells respond abnormally to environmental signals and then design and develop new therapeutic measures to prevent and treat cancer in its earliest stage.
- Apoptosis, programmed cell death
A failure of cancer cells to die. The interest in this field has been growing rapidly also in relation to Alzheimer’s disease where too many neurons die prematurely.
- Hypertension and other cardiovascular disorders
Design new treatments to reduce the incidence of hypertension, angina, and the risk of stroke and related complication
- Osteoporosis and mineral metabolism
To elucidate the mechanisms involved in bone growth and in increased mineral loss. Design and develop appropriate therapies for prevention of osteoporosis
- Infection, trauma, and sepsis
Design and develop new treatments to prevent and treat infection and sepsis. Help in the wound healing process.
- Neuroscience
To identify the mechanisms involved in the development of Alzheimer's disease, neurochemical complications in muscular dystrophy, mental disorders, neuritis, and abnormalities in neuronal development, and design appropriate therapies.
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| | | | Glycobiology Forum - News and resources for glycobiologists. | | Molecular Docking Web Site - Information about 3-D structures of proteins and the use of these to design drugs. Excellent graphics. | | Nitric Oxide Research Group - Contains overviews of Nitric Oxide, Apoptosis, and Angiogenesis as well as useful protocols. | | Protein Kinase Resource Page - Lots of nice information about protein kinases, especially protein kinase A. | | Signal Transduction Knowledge Site - Full access requires a fee; however, free "Partial Access" is available, permitting access to the Connections Maps, ST highlights, Science abstracts and summaries, Jobs, Events, and full text of Science articles after one year. | | The Integrin Page - A great starting place for information on integrins, cell adhesion, and the extracellular matrix. | | The Surfactants Virtual Library - Comprehensive site contains >1100 links to surfactant and detergent- related web sites. Includes micelles, surface tension, emulsions, applications, and more. | | The www Virtual Library of Cell Biology - This site contains protocols, excellent links, organizations and meetings, funding information, journals, and books. Highly recommended! |
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