New insights into the mechanical properties of intermediate filaments

Biological cells in an organism typically occupy fixed positions, but they can exhibit mobility under certain circumstances, such as during wound healing or the uncontrolled division and migration of tumor cells. The cytoskeleton, a network of protein filaments, provides stability, elasticity, and resistance to external forces in cells. Among these filaments, “intermediate filaments” are of particular importance. Interestingly, mobile and stationary cells contain two distinct types of intermediate filaments.

Researchers at the University of Göttingen and ETH Zurich have made significant progress in measuring and understanding the mechanical properties of these two filament types. Their findings, published in the journal Matter, reveal intriguing parallels between these biological materials and non-biological substances.

To investigate filament behavior under tension, the scientists employed optical tweezers. They attached tiny plastic beads to the ends of the filaments and manipulated them using a laser beam. This stretching technique allowed them to analyze the vimentin and keratin filaments, the two different types involved. The researchers determined the required forces for stretching and observed how these filaments responded when subjected to repeated stretching.

Surprisingly, the two types of filaments exhibited contrasting behaviors when repeatedly stretched. Vimentin filaments became softer while maintaining their length, whereas keratin filaments became longer while retaining their stiffness. These experimental results align with computer simulations of molecular interactions: vimentin filaments appear to open up, resembling multi-component gels, while keratin filaments exhibit interstructural shifts akin to metals.

Both mechanisms explain the ability of intermediate filament networks in the cytoskeleton to withstand significant deformation without sustaining damage. However, this protective characteristic arises from fundamentally different physical principles.

Dr. Charlotta Lorenz, the first author of the study, states, “These findings enhance our comprehension of why distinct cell types possess such diverse mechanical properties.”

Professor Sarah Köster, the leader of the study from Göttingen University’s Institute of X-Ray Physics, further elaborates, “We can draw inspiration from nature and contemplate the design of new, sustainable, and adaptable materials whose properties can be tailored or engineered to meet specific requirements precisely.”

Source: University of Göttingen

Leave a Comment