stressfibre

Stress fibers are transient, dynamic actin-based structures found in the cytoplasm of non-muscle cells. They are bundles of actin filaments cross-linked by myosin II motor proteins, which allow them to contract. These fibers are anchored to focal adhesions, which are sites where the cell membrane attaches to the extracellular matrix.

The formation and organization of stress fibers are crucial for various cellular processes. They play a significant role in cell adhesion, providing mechanical strength and enabling cells to resist external forces. In response to mechanical stimuli, stress fibers can remodel and reorganize, contributing to cell shape changes and migration. They are also involved in intracellular tension generation, which can influence cell division and differentiation.

The assembly of stress fibers is regulated by a complex network of signaling pathways. Rho GTPases, particularly RhoA, are key regulators that promote the assembly of stress fibers by activating downstream effectors like Rho-kinase (ROCK). External cues, such as growth factors, extracellular matrix composition, and mechanical forces, can all influence stress fiber formation.

Dysregulation of stress fiber formation has been implicated in various diseases, including cancer and fibrosis. In cancer, aberrant stress fiber dynamics can contribute to increased cell motility and invasion. In fibrotic diseases, excessive stress fiber formation and contractility can lead to tissue stiffening and organ dysfunction. Understanding the mechanisms governing stress fiber formation and function is therefore important for developing therapeutic strategies for these conditions.