Pronunciation: [stɹˈɛs fˈa͡ɪbəz] (IPA) 
The spelling of the word "Stress Fibers" in IPA phonetic transcription is /stɹɛs ˈfaɪbɚz/. The word "stress" is pronounced with the consonant cluster "str" followed by the vowel sound of "e" and the voiceless "s" sound. The word "fibers" is pronounced with the long vowel sound of "i" and the voiced "z" sound. Stress fibers are bundles of actin filaments that help cells maintain their shape and respond to mechanical stress.
Stress fibers are specialized cytoskeletal components found in cells, particularly in animal cells, that play a crucial role in maintaining cell shape, stability, and mechanical integrity. These fibers are composed of filamentous actin (F-actin) and myosin proteins and can be visually observed under light or electron microscopy.
Stress fibers are typically organized as bundles of contractile actin filaments, running parallel to each other from one end of the cell to the other. They are anchored to focal adhesions, which are protein complexes that connect the cell's cytoskeleton to the extracellular matrix or neighboring cells. These attachments provide points of structural support and enable force generation within the cell.
The main function of stress fibers is to transmit mechanical tension from the extracellular environment to the cell interior. They actively contract and exert pulling forces on focal adhesions, enabling the cell to respond to physical cues, such as stretching or mechanical resistance. Stress fibers also play a role in cell migration, as they aid in the generation of protrusions and the retraction of the cell body.
Pathological alterations in stress fiber assembly and function have been associated with various cellular dysfunctions and diseases, including cancer, fibrosis, and cardiovascular disorders. Consequently, stress fibers have become a subject of intense research and are considered important targets for therapeutic interventions aimed at restoring normal cell behavior and tissue homeostasis.
The word "stress fibers" originates from the field of cell biology. The term "stress" refers to the mechanical forces experienced by cells, which can be exerted by either external factors or internal dynamics. These forces cause cells to generate and maintain internal tension, which in turn leads to the development of intricate structures called "fibers". Thus, stress fibers are bundles of contractile proteins within cells that act as tension sensors and serve to transmit mechanical forces throughout the cell. The term "stress fibers" was coined to describe this phenomenon and is widely used in cellular research to refer to these specialized structures.
