Micromechanics and ultrastructure of actin filament networks crosslinked by human fascin: A comparison with α-actinin

Yiider Tseng, Elena Fedorov, J. Michael McCaffery, Steven C. Almo, Denis Wirtz

Research output: Contribution to journalArticle

106 Citations (Scopus)

Abstract

Fascin is an actin crosslinking protein that organizes actin filaments into tightly packed bundles believed to mediate the formation of cellular protrusions and to provide mechanical support to stress fibers. Using quantitative rheological methods, we studied the evolution of the mechanical behavior of filamentous actin (F-actin) networks assembled in the presence of human fascin. The mechanical properties of F-actin/fascin networks were directly compared with those formed by α-actinin, a prototypical actin filament crosslinking/bundling protein. Gelation of F-actin networks in the presence of fascin (fascin to actin molar ratio >1:50) exhibits a non-monotonic behavior characterized by a burst of elasticity followed by a slow decline over time. Moreover, the rate of gelation shows a non-monotonic dependence on fascin concentration. In contrast, α-actinin increased the F-actin network elasticity and the rate of gelation monotonically. Time-resolved multiple-angle light scattering and confocal and electron microscopies suggest that this unique behavior is due to competition between fascin-mediated crosslinking and side-branching of actin filaments and bundles, on the one hand, and delayed actin assembly and enhanced network micro-heterogeneity, on the other hand. The behavior of F-actin/fascin solutions under oscillatory shear of different frequencies, which mimics the cell's response to forces applied at different rates, supports a key role for fascin-mediated F-actin side-branching. F-actin side-branching promotes the formation of interconnected networks, which completely inhibits the motion of actin filaments and bundles. Our results therefore show that despite sharing seemingly similar F-actin crosslinking/bundling activity, α-actinin and fascin display completely different mechanical behavior. When viewed in the context of recent microrheological measurements in living cells, these results provide the basis for understanding the synergy between multiple cross linking proteins, and in particular the complementary mechanical roles of fascin and α-actinin in vivo.

Original languageEnglish (US)
Pages (from-to)351-366
Number of pages16
JournalJournal of Molecular Biology
Volume310
Issue number2
DOIs
StatePublished - Jul 6 2001

Fingerprint

Actinin
Actin Cytoskeleton
Actins
Elasticity
fascin
Cell Surface Extensions
Stress Fibers
Confocal Microscopy
Electron Microscopy
Proteins

Keywords

  • Rheology
  • Side-branching
  • Time-dependent confocal microscopy
  • Time-dependent multiple-angle static light scattering

ASJC Scopus subject areas

  • Virology

Cite this

Micromechanics and ultrastructure of actin filament networks crosslinked by human fascin : A comparison with α-actinin. / Tseng, Yiider; Fedorov, Elena; McCaffery, J. Michael; Almo, Steven C.; Wirtz, Denis.

In: Journal of Molecular Biology, Vol. 310, No. 2, 06.07.2001, p. 351-366.

Research output: Contribution to journalArticle

Tseng, Yiider ; Fedorov, Elena ; McCaffery, J. Michael ; Almo, Steven C. ; Wirtz, Denis. / Micromechanics and ultrastructure of actin filament networks crosslinked by human fascin : A comparison with α-actinin. In: Journal of Molecular Biology. 2001 ; Vol. 310, No. 2. pp. 351-366.
@article{330a7f0f59824a9ab287d2f98ed18bb8,
title = "Micromechanics and ultrastructure of actin filament networks crosslinked by human fascin: A comparison with α-actinin",
abstract = "Fascin is an actin crosslinking protein that organizes actin filaments into tightly packed bundles believed to mediate the formation of cellular protrusions and to provide mechanical support to stress fibers. Using quantitative rheological methods, we studied the evolution of the mechanical behavior of filamentous actin (F-actin) networks assembled in the presence of human fascin. The mechanical properties of F-actin/fascin networks were directly compared with those formed by α-actinin, a prototypical actin filament crosslinking/bundling protein. Gelation of F-actin networks in the presence of fascin (fascin to actin molar ratio >1:50) exhibits a non-monotonic behavior characterized by a burst of elasticity followed by a slow decline over time. Moreover, the rate of gelation shows a non-monotonic dependence on fascin concentration. In contrast, α-actinin increased the F-actin network elasticity and the rate of gelation monotonically. Time-resolved multiple-angle light scattering and confocal and electron microscopies suggest that this unique behavior is due to competition between fascin-mediated crosslinking and side-branching of actin filaments and bundles, on the one hand, and delayed actin assembly and enhanced network micro-heterogeneity, on the other hand. The behavior of F-actin/fascin solutions under oscillatory shear of different frequencies, which mimics the cell's response to forces applied at different rates, supports a key role for fascin-mediated F-actin side-branching. F-actin side-branching promotes the formation of interconnected networks, which completely inhibits the motion of actin filaments and bundles. Our results therefore show that despite sharing seemingly similar F-actin crosslinking/bundling activity, α-actinin and fascin display completely different mechanical behavior. When viewed in the context of recent microrheological measurements in living cells, these results provide the basis for understanding the synergy between multiple cross linking proteins, and in particular the complementary mechanical roles of fascin and α-actinin in vivo.",
keywords = "Rheology, Side-branching, Time-dependent confocal microscopy, Time-dependent multiple-angle static light scattering",
author = "Yiider Tseng and Elena Fedorov and McCaffery, {J. Michael} and Almo, {Steven C.} and Denis Wirtz",
year = "2001",
month = "7",
day = "6",
doi = "10.1006/jmbi.2001.4716",
language = "English (US)",
volume = "310",
pages = "351--366",
journal = "Journal of Molecular Biology",
issn = "0022-2836",
publisher = "Academic Press Inc.",
number = "2",

}

TY - JOUR

T1 - Micromechanics and ultrastructure of actin filament networks crosslinked by human fascin

T2 - A comparison with α-actinin

AU - Tseng, Yiider

AU - Fedorov, Elena

AU - McCaffery, J. Michael

AU - Almo, Steven C.

AU - Wirtz, Denis

PY - 2001/7/6

Y1 - 2001/7/6

N2 - Fascin is an actin crosslinking protein that organizes actin filaments into tightly packed bundles believed to mediate the formation of cellular protrusions and to provide mechanical support to stress fibers. Using quantitative rheological methods, we studied the evolution of the mechanical behavior of filamentous actin (F-actin) networks assembled in the presence of human fascin. The mechanical properties of F-actin/fascin networks were directly compared with those formed by α-actinin, a prototypical actin filament crosslinking/bundling protein. Gelation of F-actin networks in the presence of fascin (fascin to actin molar ratio >1:50) exhibits a non-monotonic behavior characterized by a burst of elasticity followed by a slow decline over time. Moreover, the rate of gelation shows a non-monotonic dependence on fascin concentration. In contrast, α-actinin increased the F-actin network elasticity and the rate of gelation monotonically. Time-resolved multiple-angle light scattering and confocal and electron microscopies suggest that this unique behavior is due to competition between fascin-mediated crosslinking and side-branching of actin filaments and bundles, on the one hand, and delayed actin assembly and enhanced network micro-heterogeneity, on the other hand. The behavior of F-actin/fascin solutions under oscillatory shear of different frequencies, which mimics the cell's response to forces applied at different rates, supports a key role for fascin-mediated F-actin side-branching. F-actin side-branching promotes the formation of interconnected networks, which completely inhibits the motion of actin filaments and bundles. Our results therefore show that despite sharing seemingly similar F-actin crosslinking/bundling activity, α-actinin and fascin display completely different mechanical behavior. When viewed in the context of recent microrheological measurements in living cells, these results provide the basis for understanding the synergy between multiple cross linking proteins, and in particular the complementary mechanical roles of fascin and α-actinin in vivo.

AB - Fascin is an actin crosslinking protein that organizes actin filaments into tightly packed bundles believed to mediate the formation of cellular protrusions and to provide mechanical support to stress fibers. Using quantitative rheological methods, we studied the evolution of the mechanical behavior of filamentous actin (F-actin) networks assembled in the presence of human fascin. The mechanical properties of F-actin/fascin networks were directly compared with those formed by α-actinin, a prototypical actin filament crosslinking/bundling protein. Gelation of F-actin networks in the presence of fascin (fascin to actin molar ratio >1:50) exhibits a non-monotonic behavior characterized by a burst of elasticity followed by a slow decline over time. Moreover, the rate of gelation shows a non-monotonic dependence on fascin concentration. In contrast, α-actinin increased the F-actin network elasticity and the rate of gelation monotonically. Time-resolved multiple-angle light scattering and confocal and electron microscopies suggest that this unique behavior is due to competition between fascin-mediated crosslinking and side-branching of actin filaments and bundles, on the one hand, and delayed actin assembly and enhanced network micro-heterogeneity, on the other hand. The behavior of F-actin/fascin solutions under oscillatory shear of different frequencies, which mimics the cell's response to forces applied at different rates, supports a key role for fascin-mediated F-actin side-branching. F-actin side-branching promotes the formation of interconnected networks, which completely inhibits the motion of actin filaments and bundles. Our results therefore show that despite sharing seemingly similar F-actin crosslinking/bundling activity, α-actinin and fascin display completely different mechanical behavior. When viewed in the context of recent microrheological measurements in living cells, these results provide the basis for understanding the synergy between multiple cross linking proteins, and in particular the complementary mechanical roles of fascin and α-actinin in vivo.

KW - Rheology

KW - Side-branching

KW - Time-dependent confocal microscopy

KW - Time-dependent multiple-angle static light scattering

UR - http://www.scopus.com/inward/record.url?scp=0035816209&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035816209&partnerID=8YFLogxK

U2 - 10.1006/jmbi.2001.4716

DO - 10.1006/jmbi.2001.4716

M3 - Article

C2 - 11428894

AN - SCOPUS:0035816209

VL - 310

SP - 351

EP - 366

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

SN - 0022-2836

IS - 2

ER -