Biologists at the University of California, San Diego have identified a new component of the cellular mechanism by which humans and animals automatically check the quality of their nerve cells to assure they're working properly during development.
In a paper published in this week's issue of the journal Neuron, the scientists report the discovery in the laboratory roundworm C. elegans of a "quality check" system for neurons that uses two proteins to squelch the signals from defective neurons and marks them for either repair or destruction.
"To be able to see, talk and walk, nerve cells in our body need to communicate with their right partner cells," explains Zhiping Wang, the lead author in the team of researchers headed by Yishi Jin, a professor of neurobiology in UC San Diego's Division of Biological Sciences and a professor of cellular and molecular medicine in its School of Medicine. "The communication is mediated by long fibers emitting from neurons called axons, which transmit electric and chemical signals from one cell to the other, just like cables connecting computers in a local wired network. In developing neurons, the journey of axons to their target cells is guided by a set of signals. These signals are detected by 'mini-receivers'proteins called guidance receptorson axons and translated into 'proceed,' 'stop,' 'turn left' or 'turn right.' Thus, the quality of these receivers is very important for the axons to interpret the guiding signals."
Jin, who is also an Investigator of the Howard Hughes Medical Institute, says defective protein products and environmental stress, such as hyperthermia, can sometimes jeopardize the health and development of cells. "This may be one reason why pregnant women are advised by doctors to avoid saunas and hot tubs," she adds.
The scientists discovered the quality check system in roundworms, and presumably other animals including humans, consists of two parts: a protein-cleaning machin
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University of California - San Diego