plasma membrane region

Definition

Target type: cellularcomponent

A membrane that is a (regional) part of the plasma membrane. [GOC:dos]

The plasma membrane region encompasses the outermost boundary of a cell, acting as a selectively permeable barrier that regulates the passage of molecules and ions into and out of the cell. It comprises a phospholipid bilayer, a fluid mosaic of lipids and proteins, with the hydrophilic heads of phospholipids facing the aqueous environment both inside and outside the cell, while the hydrophobic tails are embedded within the membrane. The plasma membrane plays a crucial role in various cellular processes, including:

* **Cell signaling:** Receptors embedded in the plasma membrane bind to signaling molecules, initiating intracellular signaling cascades.
* **Transport:** The membrane harbors transport proteins that facilitate the movement of specific molecules across the membrane, either passively through diffusion or actively against their concentration gradients.
* **Cell adhesion:** Specialized proteins and glycoproteins on the plasma membrane mediate cell-to-cell interactions and connections, forming tissues and organs.
* **Cellular identity:** The plasma membrane presents a diverse array of glycoproteins and glycolipids, contributing to the cell's unique identity and recognition by other cells.

The plasma membrane is not a static structure but rather a dynamic entity that constantly adapts to changes in the cellular environment. It exhibits fluidity due to the movement of lipids and proteins within the membrane, enabling membrane-bound organelles to move and interact. Furthermore, the plasma membrane undergoes constant remodeling, with lipids and proteins being synthesized, degraded, and replaced to maintain its integrity and function.

Several specialized regions of the plasma membrane exist, each with unique functions and characteristics. These regions include:

* **Cell junctions:** Tight junctions, adherens junctions, and gap junctions are specialized structures that connect adjacent cells, facilitating communication and maintaining tissue integrity.
* **Lipid rafts:** These microdomains are enriched in cholesterol and sphingolipids, creating platforms for the clustering of specific proteins involved in signaling and other cellular processes.
* **Caveolae:** Small invaginations in the plasma membrane that act as endocytosis sites and participate in various signaling pathways.

The plasma membrane is a vital component of all cells, serving as a dynamic barrier that regulates the flow of information and materials, allowing cells to communicate with their surroundings, maintain homeostasis, and carry out essential functions.'
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Proteins (2)

Compounds (13)