cortical endoplasmic reticulum

Definition

Target type: cellularcomponent

A cortical network of highly dynamic tubules that are juxtaposed to the plasma membrane and undergo ring closure and tubule-branching movements. [GOC:se, PMID:10931860, PMID:17686782]

The cortical endoplasmic reticulum (cER) is a specialized subdomain of the endoplasmic reticulum (ER) that is located beneath the plasma membrane in eukaryotic cells. It is characterized by its close proximity to the cell surface and its distinct morphology and function compared to the bulk ER. The cER is a dynamic and highly interconnected network of membrane-bound tubules and cisternae that extends throughout the cytoplasm and interacts extensively with other organelles, including the plasma membrane, Golgi apparatus, and mitochondria.

**Structure:**

The cER is composed of a network of interconnected tubules and cisternae that are often arranged in a parallel or sheet-like fashion. These membrane structures are typically smaller and more densely packed than the bulk ER. The cER is characterized by its close association with the plasma membrane, often forming a continuous layer just beneath the cell surface. This proximity allows for efficient communication and exchange of materials between the cER and the plasma membrane.

**Function:**

The cER plays a critical role in a wide range of cellular processes, including:

* **Lipid synthesis and metabolism:** The cER is the primary site of synthesis for phospholipids, cholesterol, and other lipids that are essential for cell membrane formation and function. It also participates in the modification and transport of lipids to other cellular compartments.
* **Calcium signaling:** The cER is a major intracellular calcium store and plays a crucial role in calcium signaling pathways. It releases calcium ions into the cytoplasm in response to various stimuli, such as hormones, neurotransmitters, and mechanical stress.
* **Protein sorting and trafficking:** The cER is involved in the initial stages of protein folding and modification. It also plays a role in the sorting and trafficking of proteins to other cellular compartments, including the Golgi apparatus and the plasma membrane.
* **Cell signaling and communication:** The cER is a major hub for signal transduction pathways. It receives signals from the plasma membrane and other cellular compartments and relays these signals to downstream targets, thereby regulating a wide range of cellular processes.
* **Cell polarity and morphogenesis:** The cER plays a crucial role in establishing and maintaining cell polarity. It also participates in cell shape changes and morphogenesis, particularly during development and differentiation.

**Regulation:**

The structure and function of the cER are tightly regulated by a variety of factors, including:

* **Cellular environment:** The cER is highly responsive to changes in the cellular environment, such as nutrient availability, stress levels, and hormonal signals.
* **Protein kinases and phosphatases:** The activity of the cER is modulated by protein kinases and phosphatases that regulate the phosphorylation state of cER proteins.
* **Small GTPases:** Small GTPases, such as Rab proteins, are involved in the trafficking of proteins and lipids to and from the cER.
* **Lipid composition:** The lipid composition of the cER membrane influences its curvature, fluidity, and interactions with other organelles.

**Disease relevance:**

Disruptions in cER function have been implicated in a variety of human diseases, including:

* **Neurodegenerative diseases:** Alterations in cER structure and function have been observed in Alzheimer's disease, Parkinson's disease, and Huntington's disease.
* **Cancer:** The cER is involved in cancer cell growth and proliferation, and dysregulation of cER function can contribute to tumor development and progression.
* **Metabolic disorders:** The cER plays a role in lipid metabolism, and disruptions in cER function can contribute to metabolic disorders, such as obesity and diabetes.

**Conclusion:**

The cER is a highly dynamic and essential organelle that plays a crucial role in a wide range of cellular processes. Its unique structure and function allow it to act as a central hub for lipid metabolism, calcium signaling, protein sorting, cell signaling, and morphogenesis. Understanding the intricate workings of the cER is essential for unraveling the complex mechanisms that govern cellular function and for developing therapeutic strategies for a variety of human diseases.'
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Proteins (2)

Compounds (14)