Traction stress in focal adhesions correlates biphasically with actin retrograde flow speed

Gardel, Margaret L.; Sabass, Benedikt; Ji, Li; Danuser, Gaudenz; Schwarz, Ulrich S.; Waterman‐Storer, Clare M.

doi:10.1083/jcb.200810060

Cited by 440 publications

(536 citation statements)

References 27 publications

Supporting

Mentioning

469

Contrasting

Unclassified

Order By: Relevance

“…3H). EA-TIRFM of αV-GFPconstrained in blebbistatin-treated cells revealed higher levels of anisotropy in NA where retrograde flow remained intact, but very low levels in the cell interior where retrograde flow was blocked (25) (Fig. 3I).…”

Section: Resultsmentioning

confidence: 99%

“…As there is no reliable way to block all retrograde flow or alter its rate without disrupting F-actin integrity, we instead asked whether there was a regional correlation between F-actin flow and integrin alignment. We used the myosin-II inhibitor blebbistatin, which abolishes myosin-II-driven flow in the lamella and FAs, but leaves actin polymerization-driven flow and cytoskeletal integrity in the lamellipodium intact (25). As expected, blebbistatin eliminated cell polarity and blocked FA elongation, leaving a rim of diffraction-limited nascent adhesions (NAs) in lamellipodia (26) (Fig.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Actin retrograde flow actively aligns and orients ligand-engaged integrins in focal adhesions

Swaminathan

Kalappurakkal

Mehta

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

112

View full text Add to dashboard Cite

Integrins are transmembrane receptors that, upon activation, bind extracellular ligands and link them to the actin filament (F-actin) cytoskeleton to mediate cell adhesion and migration. Cytoskeletal forces in migrating cells generated by polymerization-or contractilitydriven "retrograde flow" of F-actin from the cell leading edge have been hypothesized to mediate integrin activation for ligand binding. This predicts that these forces should align and orient activated, ligand-bound integrins at the leading edge. Here, polarization-sensitive fluorescence microscopy of GFP-αVβ3 integrins in fibroblasts shows that integrins are coaligned in a specific orientation within focal adhesions (FAs) in a manner dependent on binding immobilized ligand and a talin-mediated linkage to the F-actin cytoskeleton. These findings, together with Rosetta modeling, suggest that integrins in FA are coaligned and may be highly tilted by cytoskeletal forces. Thus, the F-actin cytoskeleton sculpts an anisotropic molecular scaffold in FAs, and this feature may underlie the ability of migrating cells to sense directional extracellular cues.cell migration | mechanosensing | fluorescence polarization microscopy

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Actin retrograde flow actively aligns and orients ligand-engaged integrins in focal adhesions

Swaminathan

Kalappurakkal

Mehta

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

112

View full text Add to dashboard Cite

show abstract

“…12,30,31 Furthermore, an effective connection of actin filaments to FAs can cause a deceleration of actin flow. 32,33 Keratinocytes were transfected with GFP-actin. Defined, small regions of GFP-labeled filopodial actin bundles were bleached to visualize retrograde flow ( Fig.…”

Section: Resultsmentioning

confidence: 99%

The key feature for early migratory processes

Schäfer¹,

Born²,

Möhl³

et al. 2010

Cell Adhesion & Migration

View full text Add to dashboard Cite

“…A number of studies have revealed a close connection between actomyosin dynamics and traction stresses exerted by the cell (45,46). Given our observations of traction stress modulation, we proceeded to examine how the spatial distribution and dynamics of the actomyosin cytoskeleton are regulated by MT dynamics and Rho kinase activity.…”

Section: Mt Network Forms a Radially Emanating Dynamic Array During Tmentioning

confidence: 99%

Dynamic microtubules regulate cellular contractility during T-cell activation

Hui

Upadhyaya

2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

T-cell receptor (TCR) triggering and subsequent T-cell activation are essential for the adaptive immune response. Recently, multiple lines of evidence have shown that force transduction across the TCR complex is involved during TCR triggering, and that the T cell might use its force-generation machinery to probe the mechanical properties of the opposing antigen-presenting cell, giving rise to different signaling and physiological responses. Mechanistically, actin polymerization and turnover have been shown to be essential for force generation by T cells, but how these actin dynamics are regulated spatiotemporally remains poorly understood. Here, we report that traction forces generated by T cells are regulated by dynamic microtubules (MTs) at the interface. These MTs suppress Rho activation, nonmuscle myosin II bipolar filament assembly, and actin retrograde flow at the T-cell-substrate interface. Our results suggest a novel role of the MT cytoskeleton in regulating force generation during T-cell activation.T lymphocytes, central players in the adaptive immune response, are activated when T-cell receptors (TCRs) on their surface recognize cognate peptide-major histocompatibility complex (pMHC) expressed on the surface of antigen-presenting cells (APCs). A burst of actin polymerization is triggered upon TCR stimulation (1), leading to an enhancement of the cell/APC contact area as the T cell spreads over the surface of the APC (2) and the formation of a macromolecular protein assembly known as the immunological synapse (IS) (3, 4). Accompanying IS formation, T cells also undergo a rapid polarization of the microtubule (MT) cytoskeleton, within 1-2 min after initial contact, that facilitates directional secretion of cytokines and cytolytic factors toward the APC (5-7). Therefore, the contact zone between T cells and APCs is a site at which the MT and actin cytoskeletons could potentially interact to regulate signaling.Recent studies have established that T cells generate significant traction stresses at the cell-cell interface, albeit relatively weak compared with adherent cells (8-11). These forces, which peak 5-10 min after stimulation, facilitate T-cell activation, in part, by inducing conformational changes in the TCR-CD3 complex (12-15). Although actin polymerization/depolymerization dynamics are essential for T cells to maintain dynamic traction stresses and to drive calcium influx and integrin affinity maturation (9, 16, 17), the regulatory pathways that control these cytoskeletal forces are not completely understood. In particular, whether and how the polarized MT cytoskeleton interacts with the actin cytoskeleton and regulates force generation at the T-cell-APC contact remain open questions.MTs in the cell exist in two populations: dynamic/tyrosinated MTs and stable MTs that have undergone posttranslational modifications, including detyrosination and acetylation (18). Previous studies of T-cell activation have elucidated that microtubuleorganizing center (MTOC) translocation is associated with the formati...

show abstract

Traction stress in focal adhesions correlates biphasically with actin retrograde flow speed

Abstract: Abbreviations used in this paper: CA-Rac, constitutively active Rac1; FA, focal adhesion; FSM, fl uorescent speckle microscopy; PAA, polyacrylamide.

Cited by 440 publications

References 27 publications

Actin retrograde flow actively aligns and orients ligand-engaged integrins in focal adhesions

Actin retrograde flow actively aligns and orients ligand-engaged integrins in focal adhesions

The key feature for early migratory processes

Dynamic microtubules regulate cellular contractility during T-cell activation

Contact Info

Product

Resources

About