Limits...
Talin tension sensor reveals novel features of focal adhesion force transmission and mechanosensitivity

View Article: PubMed Central - HTML - PubMed

ABSTRACT

The cytoskeletal adapter protein talin plays a prominent role in adhesive structures connecting integrins to the actin cytoskeleton. In this work, Kumar et al. use a novel talin sensor to measure talin tension and provide insights into focal adhesion force transmission and mechanosensitivity.

No MeSH data available.


Related in: MedlinePlus

Differential substrate stiffness sensing by talin and vinculin. (A) Representative FRET map and normalized FRET index of talin-TS in talin1−/− cells on stiff (∼30 kPa; n = 29) or soft (∼3 kPa; n = 30) substrates. (B) Talin-CS on stiff (n = 27) or soft (n = 26) substrates. (C) Vinculin-TS expressed in vinculin−/− cells on stiff (n = 50) or soft (n = 45) substrates. (D) Vinculin–tailless control (vinculin-TL; control for zero tension) on stiff (n = 25) or soft (n = 25) substrates. Bars, 20 µm. Error bars represent SEM.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4862330&req=5

fig4: Differential substrate stiffness sensing by talin and vinculin. (A) Representative FRET map and normalized FRET index of talin-TS in talin1−/− cells on stiff (∼30 kPa; n = 29) or soft (∼3 kPa; n = 30) substrates. (B) Talin-CS on stiff (n = 27) or soft (n = 26) substrates. (C) Vinculin-TS expressed in vinculin−/− cells on stiff (n = 50) or soft (n = 45) substrates. (D) Vinculin–tailless control (vinculin-TL; control for zero tension) on stiff (n = 25) or soft (n = 25) substrates. Bars, 20 µm. Error bars represent SEM.

Mentions: Cells on substrates of low rigidity reduce their myosin activity and exert lower traction forces, coincident with forming smaller adhesions (Wang et al., 2000; Balaban et al., 2001), though the decrease in FA size may not compensate for the reduced force under all conditions (Beningo et al., 2001). How cells sense substrate rigidity and decrease traction force is a major unanswered question. To investigate this effect at the level of talin tension, cells transfected with talin-TS or CS were plated on fibronectin-coated polydimethylsiloxane (PDMS) gels at ∼3 kPa or ∼30 kPa, the range over which fibroblasts respond to substrate stiffness (Solon et al., 2007). Cells on substrates of variable stiffness showed a transition in cell morphology between 3 and 30 kPa, a characteristic of stiffness sensing (Fig. S4, G and H). We observed consistently lower force on talin on substrates of low rigidity (Fig. 4 A), whereas talin-CS showed no difference (Fig. 4 B). Substrate stiffness did not alter the ratio of integrin β1 to talin within the FAs (Fig. S4, I–M), nor did talin FRET index show any dependence on integrin β1 intensity (Fig. S4, N–R). Next, we examined vinculin tension in this system. Remarkably, tension across vinculin was completely independent of substrate rigidity (Fig. 4, C and D). A wider range of stiffnesses gave similar results (Fig. S5, A–F). These results indicate that talin must be part of the rigidity-sensing mechanism, whereas its direct binding partner vinculin is buffered from these effects and thus must be positioned downstream of the sensing mechanism.


Talin tension sensor reveals novel features of focal adhesion force transmission and mechanosensitivity
Differential substrate stiffness sensing by talin and vinculin. (A) Representative FRET map and normalized FRET index of talin-TS in talin1−/− cells on stiff (∼30 kPa; n = 29) or soft (∼3 kPa; n = 30) substrates. (B) Talin-CS on stiff (n = 27) or soft (n = 26) substrates. (C) Vinculin-TS expressed in vinculin−/− cells on stiff (n = 50) or soft (n = 45) substrates. (D) Vinculin–tailless control (vinculin-TL; control for zero tension) on stiff (n = 25) or soft (n = 25) substrates. Bars, 20 µm. Error bars represent SEM.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4862330&req=5

fig4: Differential substrate stiffness sensing by talin and vinculin. (A) Representative FRET map and normalized FRET index of talin-TS in talin1−/− cells on stiff (∼30 kPa; n = 29) or soft (∼3 kPa; n = 30) substrates. (B) Talin-CS on stiff (n = 27) or soft (n = 26) substrates. (C) Vinculin-TS expressed in vinculin−/− cells on stiff (n = 50) or soft (n = 45) substrates. (D) Vinculin–tailless control (vinculin-TL; control for zero tension) on stiff (n = 25) or soft (n = 25) substrates. Bars, 20 µm. Error bars represent SEM.
Mentions: Cells on substrates of low rigidity reduce their myosin activity and exert lower traction forces, coincident with forming smaller adhesions (Wang et al., 2000; Balaban et al., 2001), though the decrease in FA size may not compensate for the reduced force under all conditions (Beningo et al., 2001). How cells sense substrate rigidity and decrease traction force is a major unanswered question. To investigate this effect at the level of talin tension, cells transfected with talin-TS or CS were plated on fibronectin-coated polydimethylsiloxane (PDMS) gels at ∼3 kPa or ∼30 kPa, the range over which fibroblasts respond to substrate stiffness (Solon et al., 2007). Cells on substrates of variable stiffness showed a transition in cell morphology between 3 and 30 kPa, a characteristic of stiffness sensing (Fig. S4, G and H). We observed consistently lower force on talin on substrates of low rigidity (Fig. 4 A), whereas talin-CS showed no difference (Fig. 4 B). Substrate stiffness did not alter the ratio of integrin β1 to talin within the FAs (Fig. S4, I–M), nor did talin FRET index show any dependence on integrin β1 intensity (Fig. S4, N–R). Next, we examined vinculin tension in this system. Remarkably, tension across vinculin was completely independent of substrate rigidity (Fig. 4, C and D). A wider range of stiffnesses gave similar results (Fig. S5, A–F). These results indicate that talin must be part of the rigidity-sensing mechanism, whereas its direct binding partner vinculin is buffered from these effects and thus must be positioned downstream of the sensing mechanism.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

The cytoskeletal adapter protein talin plays a prominent role in adhesive structures connecting integrins to the actin cytoskeleton. In this work, Kumar et al. use a novel talin sensor to measure talin tension and provide insights into focal adhesion force transmission and mechanosensitivity.

No MeSH data available.


Related in: MedlinePlus