growth cone membrane

Definition

Target type: cellularcomponent

The portion of the plasma membrane surrounding a growth cone. [GOC:mah]

The growth cone membrane is a specialized structure at the tip of growing axons and dendrites, responsible for guiding the neuron's extension towards its target. It is characterized by a unique composition of proteins, lipids, and carbohydrates that facilitate its dynamic and highly responsive nature. The cellular component of the growth cone membrane can be broken down into several key elements:

* **Plasma membrane:** This forms the outermost boundary of the growth cone and is enriched in specific lipids like phosphatidylinositol 4,5-bisphosphate (PIP2), which plays a crucial role in signaling pathways. The plasma membrane also houses a variety of receptors, ion channels, and transporters responsible for receiving and transducing external cues.
* **Actin cytoskeleton:** A dense network of actin filaments underlies the plasma membrane, providing structural support and driving the dynamic shape changes of the growth cone. Actin polymerization and depolymerization are tightly regulated by signaling pathways, allowing the growth cone to respond to guidance cues and extend filopodia and lamellipodia.
* **Microtubules:** These long, stiff polymers of tubulin protein extend from the cell body into the axon and reach the growth cone, providing a framework for axonal transport and delivering essential proteins and organelles. Microtubules are involved in the establishment and maintenance of growth cone polarity.
* **Signaling molecules:** The growth cone membrane is densely populated with various signaling molecules, including receptors, kinases, phosphatases, and second messengers. These molecules transduce extracellular cues into intracellular signals, controlling actin dynamics, microtubule stability, and gene expression, ultimately directing the growth cone's movement.
* **Adhesion molecules:** These proteins allow the growth cone to adhere to its environment, providing traction for movement and guiding its navigation along specific pathways. Adhesion molecules include cell-cell adhesion molecules (CAMs) and extracellular matrix (ECM) receptors.
* **Vesicles:** Small membrane-bound compartments filled with various molecules, including neurotransmitters, enzymes, and structural components, are present within the growth cone membrane. These vesicles are involved in membrane trafficking, synaptic transmission, and growth cone expansion.
* **Mitochondria:** These powerhouses of the cell are present within the growth cone, providing energy for its highly demanding activities, including cytoskeletal reorganization, signal transduction, and membrane transport.

The cellular component of the growth cone membrane is a highly dynamic and intricate structure, essential for navigating the developing nervous system and establishing precise neuronal connections.'
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Proteins (1)

Compounds (7)