what is the difference between fast and slow axonal transport

Ribosomes and ribonucleoprotein particles, whose movement is important in axon development and regenera- tion, may also move by fast axonal transport. In contrast to fast axonal transport, slow axonal transport represents the movement of proteins that make up the cytoskeleton and cytosol of axons.

Full Answer

What is slow axonal transport?

Slow axonal transport is the movement of cytoskeletal polymers and cytosolic protein complexes along axons at average rates on the order of millimeters per day, which corresponds to nanometers per second.

What is fast axon transport?

Cytoskeleton and Intracellular Motility Fast axonal transport describes the bidirectional movement of organelles along the length of an axon. The cytoplasmic contents or axoplasm of a giant axon can be extruded from the surrounding plasma membrane, much like squeezing toothpaste from a toothpaste tube.

What is retrograde fast axonal transport?

Retrograde fast axonal transport is exploited by the herpes viruses, a large group that includes the pathogenic agents responsible for cold sores (herpes simplex virus I, HSV1), genital herpes (herpes simplex virus II, HSV2), chicken pox and shingles (varicella-zoster virus, VZV).

What is fast axonal transport in squid?

Fast axonal transport describes the bidirectional movement of organelles along the length of an axon. The squid Loligo pealeii possesses a “giant” (1 mm) axon that contributes to its ability to escape predators by rapidly expelling a jet of water out its funnel, propelling the squid away from danger.

What is fast axonal transport?

Fast Axonal Transport is the Rapid Movement of Membrane Vesicles and Their Contents over Long Distances within a Neuron. Early biochemical and morphological studies established that material moving in fast axonal transport was associated with membrane-bound organelles (Fig. 2.9).

What are the 2 types of axonal transport?

Figure 3 - (A) Axonal transport can occur in two directions: anterograde transport is from the cell body toward the axon tip, and retrograde transport is from the axon tip back toward the cell body.

What is the function of slow axonal transport?

This suggests that critical roles are played by the slow axonal transport proteins in growth and regeneration. During development, SCb proteins are prominent and relatively little NF protein is detectable. Tubulin can be detected moving at both SCb and SCa rates.

What is slow anterograde transport?

There are two classes of slow anterograde transport: slow component a (SCa) that carries mainly microtubules and neurofilaments at 0.1-1 millimeters per day, and slow component b (SCb) that carries over 200 diverse proteins and actin at a rate of up to 6 millimeters per day.

What is fast axonal transport quizlet?

fast axonal transport uses this method of movement of materials from synaptic knobs to the cell body. Used vesicles to be broken down and recycled, and potentially harmful agents, are moved via retrograde transport from the synaptic knob to the cell body (backward).

How fast is fast axonal transport?

Fast anterograde transport represents movement of MBOs along MTs away from the cell body at rates ranging in mammals from 200 to 400 mm per day or from 2 to 5 μm per second [3,10].

Does fast axonal transport require ATP?

Fast axonal transport (FAT) requires consistent energy over long distances to fuel the molecular motors that transport vesicles. We demonstrate that glycolysis provides ATP for the FAT of vesicles.

What type of axonal transport allows certain viruses?

Retrograde axonal transport is not only used to transfer physiological materials back to the cell body from the periphery, but also is an important pathway for some neurotropic viruses to invade the CNS.

What is axonal transport?

Jump to navigation Jump to search. Axonal transport, also called axoplasmic transport or axoplasmic flow, is a cellular process responsible for movement of mitochondria, lipids, synaptic vesicles, proteins, and other organelles to and from a neuron 's cell body, ...

How fast does a vesicular cargo move?

Vesicular cargoes move relatively fast (50–400 mm/day) whereas transport of soluble (cytosolic) and cytoskeletal proteins takes much longer (moving at less than 8 mm/day). The basic mechanism of fast axonal transport has been understood for decades but the mechanism of slow axonal transport is only recently becoming clear, as a result of advanced imaging techniques. Fluorescent labeling techniques (e.g. fluorescence microscopy) have enabled direct visualization of transport in living neurons. (See also: Anterograde tracing .)

What causes distal axon degeneration?

Since the axon depends on axoplasmic transport for vital proteins and materials, injury, such as diffuse axonal injury, which interrupts the transport, will cause the distal axon to degenerate in a process called Wallerian degeneration.

What is the parent protein of anterograde transport motors?

A cargo-receptor for anterograde transport motors, the kinesins, has been identified as the amyloid precursor protein (APP), the parent protein that produces the senile plaques found in Alzheimer's disease.

What is retrograde transport?

Retrograde transport shuttles molecules/organelles away from axon termini toward the cell body. Retrograde axonal transport is mediated by cytoplasmic dynein, and is used for example to send chemical messages and endocytosis products headed to endolysosomes from the axon back to the cell. Operating at average in vivo speeds of approximately 2 μm/sec, fast retrograde transport can cover 10-20 centimeters per day.

Which protein is responsible for the transportation of cargoes in the axon?

Microtubules (made of tubulin) run along the length of the axon and provide the main cytoskeletal "tracks" for transportation. Kinesin and dynein are motor proteins that move cargoes in the anterograde (forwards from the soma to the axon tip) and retrograde (backwards to the soma (cell body)) directions, respectively.

Where are axonal proteins synthesized?

The vast majority of axonal proteins are synthesized in the neuronal cell body and transported along axons. Some mRNA translation has been demonstrated within axons. Axonal transport occurs throughout the life of a neuron and is essential to its growth and survival. Microtubules (made of tubulin) run along the length of the axon and provide ...

What is fast axonal transport?

Fast axonal transport (FAT) is significantly impaired in a number of neurodegenerative diseases, including tauopathies, and these defects have been linked to alterations in the normal function of tau (reviewed in Ref. 125 ). For example, in cellular models in which tau was overexpressed, a disruption in the trafficking of membranous vesicles and mitochondria was found. 126–130 Similarly, various mouse models of tauopathy in which wild-type or mutant tau was expressed also demonstrated impaired axonal transport. 131,132 The ability of tau to interfere with axonal transport may arise through direct interactions between tau and transport motor complexes. In fact, tau was able to associate with kinesin, as demonstrated by immunofluorescence and co-immunoprecipitation experiments. 133,134In vitro experiments have further identified a direct interaction between tau and kinesin, 135,136 and between tau and the p150 protein in the dynein–dynactin motor complex. 137 Moreover, these direct interactions between tau and motors decreased the ability of kinesin to attach to microtubules 138 and increased the rate of motor detachment from microtubules, 139,140 although the above studies also reported conflicting data concerning whether tau altered overall cargo transport rates. As these results have shown, the effects of tau on axonal transport may be more complex than simply blocking motor access to the microtubules. For instance, an interaction between tau and c-Jun N-terminal kinase-interacting protein 1 (JIP1) has been proposed to affect the kinesin-I motor complex, causing a relocalization of JIP1 and impaired axonal transport. 141 Also, in Aplysia, tau overexpression was capable of causing both a complete stop in transport and a reorganization of microtubule polarity within the axon. 142 The conformation of tau may influence FAT as well since studies performed using squid axoplasm showed that soluble monomeric tau did not affect transport 143 whereas tau filaments or N-terminal fragments significantly reduced transport using a mechanism involving PP1, GSK-3β, and the light chain of the kinesin motor. 144

What is the axonal transport of cholinergic vesicles?

The fast axonal transport supplies cholinergic synaptic vesicles with proteins, glycoproteins and phospholipids. However the time of sojourn of these macromolecular components in the population of cholinergic vesicles may vary from a few hours for a protein fraction to several days for a glycoprotein fraction (1, 6 ).

What are exogenous materials taken up in distal regions of axons?

In addition, exogenous materials taken up in distal regions of axons may be moved back to the cell body by retrograde transport ( Fig. 2.9 ). Exogenous materials in retrograde transport include neurotrophins, such as nerve growth factor, and viral particles invading the nervous system.

Which MAP kinase is activated at axonal injury sites and is retrogradely transported

Another MAP kinase member, the Aplysia protein kinase G (ApPKG), is activated at axonal injury sites and retrogradely transported, but the mechanism responsible for injury-induced retrograde transport is still unknown.

How are cytoskeletal proteins transported?

Soluble cytoskeletal proteins such as tau, kinesin, dynein, myosin, and tubulin are transported at a rate of approximately 1 mm day –1 by slow axonal transport. Membrane-bound proteins, associated with organelles such as presynaptic precursor vesicles, are transported at a rate of approximately 1 μm s –1 by fast axonal transport.

What is the difference between a synapse and a neuromuscular junction?

The key difference synapse and neuromuscular junction is that synapse is a junction between two nerve cells or between a neuron and a muscle cell, while neuromuscular junction is a junction between a motor neuron and a muscle fiber. Sensory transduction is the process that converts one sensory stimulus from one form to another. Transduction ]

What is the difference between carbonyl and nitrosyl complexes?

The key difference between carbonyl and nitrosyl complexes is that carbonyl complexes contain -CO ligands, whereas nitrosyl complexes contain -NO ligands. Coordination complexes are inorganic complexes containing a central atom or an ion (typically a metal ion) and surrounding molecules named ligands that are bound to the central atom or ion. The central atom or ]

Overview

Fast and slow transport

Vesicular cargoes move relatively fast (50–400 mm/day) whereas transport of soluble (cytosolic) and cytoskeletal proteins takes much longer (moving at less than 8 mm/day). The basic mechanism of fast axonal transport has been understood for decades but the mechanism of slow axonal transport is only recently becoming clear, as a result of advanced imaging techniques. Fluorescent labeling techniques (e.g. fluorescence microscopy) have enabled direct visualizatio…

Mechanism

Anterograde transport

Retrograde transport

Consequences of interruption

Infection

See also