Abstract
The cytoskeleton of eukaryotic cells is primarily composed of networks of filamentous proteins, F-actin, microtubules, and intermediate filaments. Interactions among the cytoskeletal components are important in determining cell structure and in regulating cell functions. For example, F-actin and microtubules work together to control cell shape and polarity, while the subcellular organization and transport of vimentin intermediate filament (VIF) networks depend on their interactions with microtubules. However, it is generally thought that F-actin and VIFs form two coexisting but separate networks that are independent due to observed differences in their spatial distribution and functions. In this paper, we present a closer investigation of both the structural and functional interplay between the F-actin and VIF cytoskeletal networks. We characterize the structure of VIFs and F-actin networks within the cell cortex using structured illumination microscopy and cryoelectron tomography. We find that VIFs and F-actin form an interpenetrating network (IPN) with interactions at multiple length scales, and VIFs are integral components of F-actin stress fibers. From measurements of recovery of cell contractility after transient stretching, we find that the IPN structure results in enhanced contractile forces and contributes to cell resilience. Studies of reconstituted networks and dynamic measurements in cells suggest direct and specific associations between VIFs and F-actin. From these results, we conclude that VIFs and F-actin work synergistically, both in their structure and in their function. These results profoundly alter our understanding of the contributions of the components of the cytoskeleton, particularly the interactions between intermediate filaments and F-actin.
Original language | English (US) |
---|---|
Article number | e2115217119 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 119 |
Issue number | 10 |
DOIs | |
State | Published - Mar 8 2022 |
Funding
ACKNOWLEDGMENTS. We gratefully acknowledge Dr. Bomi Gweon for insightful discussions and assistance with traction force measurements. This work was supported in part by NIH Grants 2P01GM096971 awarded to R.G. and D.A.W. and 1R01HL148152 and 1U01CA202123 awarded to J.J.F. D.A.W. also acknowledges support from the Harvard Materials Research Science and Engineering Center Grants DMR-1420570 and DMR-2011754. O.M. acknowledges support by The Swiss National Foundation, Grant 31003A_179418. M.S.W. was funded by the Forschungskredit fellowship from the University of Zurich. Y.S. was supported by the NSF–Simons Center for Mathematical and Statistical Analysis of Biology at Harvard (NSF Award 1764269) and the Harvard Quantitative Biology Initiative.
Keywords
- Cell cortex
- High-resolution imaging
- Interpenetrating networks of F-actin and vimentin intermediate filaments
- Traction force microscopy
ASJC Scopus subject areas
- General