Author: Aldiyarbek Nurlan
Translator: Tursunova Balkadisha
Editor: Akhmetova Aigerim
"Dendritic branching of neurons is one of the fascinating features that has led to an increase in the complexity of interactions between neurons. However, the more complex dendritic branch also increases the complexity of the logistical task of delivering proteins to each part of the neuron, " the researchers say.
Neurons distribute thousands of different types of proteins needed to maintain synaptic function and the plasticity of their dendritic branches. However, most proteins are synthesized hundreds of microns away from the distal synapses, in the soma (its cell body). How do proteins reach the distal areas? "In this study, we focused on passive protein transport, which corresponds to free diffusion. Unlike active transport via molecular engines, diffusion is energy-cheap. However, there is a downside: passive transport is slow and non-directional, " the researchers explain.
What happens when proteins meet the branching points of dendrites? Branching points are like intersections for traffic: some squirrels turn right, others turn left. Intersections for cars can be traffic bottlenecks. Similarly, the more branching point proteins that occur along the way, the lower the total number of downstream proteins. As a result, the neuron needs to produce more proteins to maintain the minimum amount of protein in the distal synapses.
Each protein has a typical distance that it can travel during diffusion, this is its diffusion length. The higher this value, the more proteins will reach the distal dendrites. If the dendritic branch has a large radius, it can carry more proteins. A combination of two factors, the width (or "radius") of the dendrites and how far the proteins can travel, determines the number of proteins the neuron must produce to provide all synapses. The researchers found that by optimizing dendritic radii, the neuron can reduce the total amount of protein and, consequently, the cost of protein synthesis by several orders of magnitude.
"Our results show that the morphology of neuronal dendrites plays a key role in shaping neuronal function and reflects optimization strategies and restrictions imposed by protein traffic," the researchers conclude.
Source: https://www.sciencedaily.com/releases/2020/11/201123101012.htm
