( A motor protein called myosin X runs th...)Motor protein plays key role in connecting neurons

In another piece of the puzzle of how neurons form connections, researchers have found myosin X travels a portion of a neuron's backbone called the actin filament, a sort of two-way highway in the cell's highest traffic area, says Dr. Wen-Cheng Xiong, developmental neurobiologist at the Medical College of Georgia.

Part of its cargo is DCC receptor which needs to move from the central nucleus where it's synthesized to the cell's periphery, Dr. Xiong and her colleagues report in the February issue of Nature Cell Biology and available online Jan. 21.

At the periphery, DCC interacts with netrin-1, a guidance cue for helping the arm-like extension of the cell, called the axon, grow in the right direction. Cells eventually communicate through synapses at the end of these cellular projections.

"During early development, axons need to grow, they need to find a target, they need to decide how long to grow, which direction to grow. Eventually they will form a synapse," says Dr. Xiong, who is dissecting how neurons first connect with the goal of helping restore communication lost in spinal cord injuries and other disorders.

"Growth is precisely controlled during development," she says and errant growth can impair brain wiring or connectivity. "Myosin X gets the DCC receptor where it needs to be so it can interact with netrin-1."

Her previous studies, published in 2004 in Nature Neuroscience, showed that DCC binding to netrin-1, activates an enzyme, focal adhesion kinase, enabling developing cells to reorganize and intuitively know how to move. The process enables brain cells to reach out to each other and across the midline of the developing brain and spinal cord. When the kinase is deleted, the axon doesn't make the proper connectio
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Source:Medical College of Georgia