negative regulation of actin filament severing

Definition

Target type: biologicalprocess

Any process that stops, prevents or reduces the frequency, rate or extent of actin filament severing. [GO_REF:0000058, GOC:als, GOC:TermGenie, PMID:23325791]

Negative regulation of actin filament severing is a critical process that controls the dynamic organization of the actin cytoskeleton, a network of filamentous proteins that plays essential roles in cell motility, division, and shape. Actin filaments, which are polymers of the protein actin, are constantly being assembled and disassembled through the coordinated action of actin-binding proteins. Severing proteins, such as cofilin and gelsolin, can break actin filaments into shorter fragments, increasing the number of free ends available for polymerization and depolymerization. This process contributes to the rapid reorganization of the actin cytoskeleton, allowing cells to respond to changes in their environment. However, unchecked severing can disrupt the integrity of the cytoskeleton, leading to cellular dysfunction.

Negative regulation of actin filament severing ensures that the actin cytoskeleton remains stable and functional. This regulation can occur at multiple levels, including:

**1. Inhibition of severing protein activity:** Severing proteins, such as cofilin and gelsolin, are often regulated by post-translational modifications, such as phosphorylation. Phosphorylation can decrease the affinity of these proteins for actin filaments, reducing their ability to sever.

**2. Competition for actin binding sites:** Other actin-binding proteins, such as profilin, can compete with severing proteins for binding sites on actin filaments. This competition prevents severing proteins from accessing the filament and reduces their activity.

**3. Protection of actin filaments:** Actin-binding proteins, such as tropomyosin, can bind along the length of actin filaments, shielding them from severing proteins. This protective mechanism helps to maintain the structural integrity of the cytoskeleton.

**4. Regulation of severing protein localization:** Severing proteins are often localized to specific regions of the cell, where they are required for specific functions. This localization can be regulated by factors such as membrane association, cytoskeletal binding, or protein-protein interactions.

**5. Regulation of severing protein expression:** The levels of severing proteins can be controlled by transcriptional and translational regulation. This allows for the fine-tuning of severing activity in response to cellular needs.

In summary, negative regulation of actin filament severing is a complex process that involves multiple mechanisms to control the activity of severing proteins and maintain the integrity of the actin cytoskeleton. This process is crucial for a wide range of cellular functions, including cell motility, division, and shape.'
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Proteins (1)

Compounds (1)