The key difference between anterograde and retrograde transport is that anterograde transport moves physiological materials towards presynaptic terminals while retrograde transport moves physiological materials back to the cell body from the periphery.
Axonal transport is a physiological process that transports proteins and other substances synthesized in the neurosome to the nerve endings through the cytoskeleton. In simple words, it is the process that involves the material transfer between the cell body and the axonal terminal of neurons. Axons are capable of bidirectional transport. Based on the direction of the material flow, there are two categories of axonal transport: anterograde and retrograde axonal transport. In anterograde transport, materials are transported towards the presynaptic terminals while in retrograde transport, materials are transported from the periphery towards the cell body. Moreover, motor kinesins facilitate anterograde transport while motor dyneins facilitate retrograde transport.
CONTENTS
1. Overview and Key Difference
2. What is Anterograde Transport
3. What is Retrograde Transport
4. Similarities Between Anterograde and Retrograde Transport
5. Side by Side Comparison – Anterograde vs Retrograde Transport in Tabular Form
6. Summary
What is Anterograde Transport?
Anterograde transport is one of the two types of axonal transport. In anterograde transport, materials are transported towards the presynaptic terminals. Through this process, nutrients, organelles, and other molecules are transported from the soma (cell body) to the distal axon. Anterograde transport is facilitated by cytoplasmic motors kinesins. Anterograde transport is important since it provides newly synthesized components such as membrane-associated enzymes, neurotransmitters, neuropeptides and membrane lipids, which are essential for neuronal membrane function and maintenance.
Figure 01: Anterograde and Retrograde Transport
What is Retrograde Transport?
Retrograde transport is the process by which physiological materials are transported back to the cell body (soma) from the periphery (axon). This process allows the returning of membrane molecules to the cell body for degradation by acid hydrolases present in lysosomes.
Figure 02: Retrograde Transport
Materials which are to be delivered to lysosomes in the cell body are mainly transported via retrograde transport. It is also an important pathway for some neurotropic viruses to invade the central nervous system. Retrograde transport is facilitated by cytoplasmic motors dyneins. Dynein moves toward the minus end of the microtubule, which is oriented toward the cell body.
What are the Similarities Between Anterograde and Retrograde Transport?
- Anterograde and retrograde transport are two categories of axonal transport.
- These processes transport materials from the soma towards the axon and from axon towards the soma.
- Cytoplasmic motors facilitate these processes.
What is the Difference Between Anterograde and Retrograde Transport?
Anterograde transport is the process of transporting physiological materials from the cell body to axon while retrograde transport is the process of transporting physiological materials from axon to the cell body. So, this is the key difference between anterograde and retrograde transport. Also, motor kinesins facilitate anterograde transport while cytoplasmic motor dyneins facilitate retrograde transport.
Moreover, another difference between anterograde and retrograde transport is that materials such as membrane-associated enzymes, neurotransmitters, neuropeptides and membrane lipids are transported via anterograde transport while materials that should be delivered to lysosomes in the cell body are transported via retrograde transport.
Below is a summary tabulation of the differences between anterograde and retrograde transport.
Summary – Anterograde vs Retrograde Transport
Axonal transport is bidirectional. Based on the direction, it can be anterograde transport or retrograde transport. Anterograde transport involves transporting materials from the soma to the distal axon. In contrast, retrograde transport involves transporting material from distal regions to soma. Thus, this is the key difference between anterograde and retrograde transport. Motor kinesins are involved in anterograde transport. Motor dyneins are involved in retrograde transport.
Reference:
1. Stenoien, David L. “Fast Axonal Transport.” Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th Edition., U.S. National Library of Medicine, 1 Jan. 1999, Available here.
2.”Axoplasmic Transport – An Overview | Sciencedirect Topics”. Sciencedirect.Com, 2020, Available here.
Image Courtesy:
1. “Microtúbulos motores” By Duncan J.E., Goldstein L.S.B. – The Genetics of Axonal Transport and Axonal Transport Disorders PLoS Genet 2(9):e124. (CC BY 4.0) via Commons Wikimedia
2. “Cytoplasmic dynein” By User:Delldot – Own work (CC BY 3.0) via Commons Wikimedia
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