Curr Biol: the key protein of "braking" in nerve growth

November 1, 2019 news / BIOON / -- in the process of embryonic development, nerve cells will form elongated extension structures, which can be used to connect complex brain networks Recently, scientists from Germany's Center for neurodegenerative diseases (dzne) have identified a protein that "blocks" the growth of these neuronal extension structures In the long run, their findings may help to develop new methods for the treatment of spinal cord injury The study was published in the journal Current Biology Neurons have "polarization" characteristics, so they can transmit signals in a specific direction After receiving the signal, the neuron transmits it to the next cell through the long axon In humans, axons in the spinal cord may be longer than one meter So, is it possible to restore this growth potential of neurons after spinal cord injury? "To answer this question, we first need to better understand the molecular process of neuronal development during embryonic development," said Professor Frank bradke, director of the dzne Bonn research center Now, he and his colleagues have taken a step toward that goal by studying the growth of neurons in mice and cell cultures (photo source: www Pixabay Com) the core of this study is a protein called RhoA RhoA interacts with many protein chaperones and has different functions in many cells However, its exact function in neurons has not been determined "For a long time, it has been thought that RhoA determines the polarity of neurons and thus the location of axon formation in cells," bradke explained Current studies have shown that this is not the case: RhoA is independent of cell polarity and axon size In contrast, RhoA works only when axons are formed and their extension is regulated by molecular cascade This insight may be important for the development of new therapies "Manipulating the RhoA signaling pathway should only affect the growth of nerve fibers, not the internal tissue of cells," bradke said Like any other cell, neuron cells have a skeleton which provides structure for them Bradke and his colleagues demonstrated that RhoA activates a molecular signaling pathway that directly targets the cytoskeleton RhoA inhibits axon elongation by limiting the entry of cytoskeleton components necessary for microtubule axon stabilization into the axon growth zone "In embryonic development, this growth brake may be necessary to coordinate different development processes Now, accurate understanding of its molecular basis may be helpful to promote the research of spinal cord regeneration after injury The lead author of the study, Dr Sebastian dupraz, a postdoctoral researcher at bradke laboratories, said "The molecular cascades we have identified directly affect the cytoskeleton of axons, thus providing a good starting point for therapeutic strategies." In previous studies, bradke's team found that proteins, the cofilin / ADF family, also play an important role in axon growth Because RhoA and cofilin / ADF proteins act on the cytoskeleton of axons in different ways Therefore, both approaches may be potential targets for future treatment Information source: a protein that pulls the brake on energy growth original source: Sebastian dupraz et al RhoA controls axon extension independent of specification in the developing brain Current biology, 2019 doi: 10.1016/j.cub.2019.09.040