Microtubules: Role in axon and dendrites formation

Polarized cells such as neurons have two distinct domains i.e. molecular and functional domains which have been emerged from the cell body. In neurons, axon and dendrites are two distinct functional units emerged from the cell body by the process called neuronal polarity. Axons are thin, single and long structure which will transmit the signals to the target or synaptic partner. Whereas dendrites are shorter, multiple structures which has the ability to receive signals from different regions of cells or axons. Before getting with role of microtubules in axon and dendrite formation, we need to look into the neuronal polarity part which...

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Growth cone and its role in axonal guidance

Growth cone are specialized and highly motile cellular compartment at the tips of the growing axon which supports the growth of the axon by sensing the extracellular cues and transducing it to the cytoskeletons. The structure consists of a central region filled with organelles and microtubules; whereas at the peripheral region, it has highly dynamic, actin rich region such as Lamellipodia and Filopodia. Lamellipodia are the broad veil like cellular protrusions that contain branched actin filaments. Filopodia are thin protrusions made out of unbranched and parallel F actin bundles.  ...

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Axonal initial segment

Information flows along a neuron in one direction i.e. synapse to cell body, then to axon initial segment (AIS), from their its passed to Axon and then to terminal region. Actually, neurons will receive both excitatory and inhibitory synaptic inputs on their cell bodies and dendrites. The fire of the repeated synaptic inputs will be summated and bursted out as action potential which will be taken cared by AIS. Axonal initial segment (AIS) is made up of high densities of voltage gated Na+ and K+ channels which initiate and modulate action potential. In the myelinated axons of vertebrates, the propagation of action potential is rapid along the...

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Centrosome role in neuronal polarity

Centrosome or MTOC (Microtubule organizing center) is a kind of organelle found in both plant and animal cell which guides the formation of microtubule in the cell. Microtubule array arises from the Centrosome and spreads all over the structure of the normal cell. But in the case of developing neuron, the Centrosome is localized towards one particular neurite and then the microtubules are guided to that neurite which further forms the axon. Centrosome positioning is an important phenomenon in the neuronal polarity because out of all the neurite; one specific axon has to be formed towards the target cell or neuron. Centrosome positioning...

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