Abstract

Intermediate filaments (IFs) are a diverse group of fibrous proteins that contribute significantly to the mechanical integrity and structural resilience of cells. Unlike actin filaments and microtubules, IFs exhibit considerable heterogeneity in their protein composition across different cell types and tissues. This review explores the fundamental roles of IFs as essential components of the cytoskeleton, focusing on their unique structural characteristics and functional implications. IFs are characterized by their intermediate size (between actin and microtubules) and their ability to form robust networks that provide mechanical strength to cells and tissues. They play crucial roles in maintaining cell shape, stabilizing organelle positioning, and resisting mechanical stress. The diversity of IF proteins, including keratins, vimentin, desmin, and neurofilaments, reflects their specialized functions in various cell types, such as epithelial cells, muscle cells, and neurons.

The assembly and regulation of IFs are tightly controlled processes involving specific assembly factors and posttranslational modifications. These mechanisms dictate the formation of IF networks and their adaptation to cellular conditions and developmental stages. Dysregulation of IF dynamics is associated with numerous human diseases, including skin disorders, muscular dystrophies, and neurodegenerative conditions. Understanding the intricate roles of IFs in cellular mechanics and pathology is essential for advancing biomedical research and developing therapeutic strategies. This review integrates current knowledge on IF structure, function, and regulation, highlighting their pivotal contributions to cell strength, flexibility, and tissue integrity in health and disease.