During the development of a nervous system, axons, a threadlike extension of a nerve cell, undergo a long and complex targeting process to reach appropriate brain areas, so as to establish synaptic connections and build functional neural networks. Thus, correct axonal guidance and targeting are essential for normal brain function, while defects in axonal growth and guidance lead to neurological disorders such as mental retardation and epilepsy. Althought neuroscientists have discovered that netrin is a secreted protein with important roles in axonal growth and guidance in the developing nervous system, they are puzzled about the mechanisms henind it.
A collaborative study between Dr. DING Yu-Qiang from the Institute of Neuroscience, the CAS Shanghai Institutes for Biological Sciences, and Dr. XIONG Wen-Cheng from the Medical College of Georgia (USA) has revealed a new intracellular pathway for Netrin signaling. As reported online in
Nature Cell Biology on January 21, they discovered that an unconventional myosin, Myosin X, directly interacts with intracellular domain of DCC, the Netrin receptor, and cargos DCC to the tips of growing axons for sensing Netrin levels. The scientists observed that both
in vivo and
in vitro data clearly indicate that disruption of the interactions between Myosin X and DDC results in a failure of Netrin-induced axonal growth and projections.
