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SUMMARY:Non-equilibrium fluctuations and mechanics of active gels and livi
 ng cells - Fred Mackintosh\, Department of Physics and Astronomy\, Vrije U
 niversiteit
DTSTART:20090508T131500Z
DTEND:20090508T141500Z
UID:TALK17215@talks.cam.ac.uk
CONTACT:Kevin Chalut
DESCRIPTION:Much like the bones in our bodies\, filamentous proteins make 
 up the cytoskeleton that largely determines the mechanical response and st
 ability of cells. Such important cellular processes as locomotion\, cell d
 ivision and the sensing of mechanical stimuli are largely governed by comp
 lex networks of cytoskeletal biopolymers and the associated proteins that 
 cross-link these and/or generate forces within the network. In addition to
  their important role in cell mechanics\, cytoskeletal biopolymers have al
 so provided new insights and challenges for polymer physics and rheology. 
 Biopolymer networks\, for instance\, exhibit strongly nonlinear rheology
 —in many cases stiffening by orders of magnitude when subject to shear s
 trains of less than unity. In the cell\, these polymer networks or gels ar
 e far from equilibrium in a way unique to biology: they are subject to act
 ive\, non-thermal internal forces generated by molecular motors. We descri
 be recent theoretical and experimental results on active networks in vitro
  that demonstrate significant non-equilibrium fluctuations due to motor ac
 tivity [1\,2]. Furthermore\, such gels hold out the promise of active mate
 rials\, whose stiffness can be controlled by enzymatic activity. We also s
 how how fluctuations and dynamics of individual cytoskeletal filaments can
  be used to probe both mechanical properties and non-equilibrium activity 
 in living cells [3\,4]. \n\n1. D Mizuno\, C Tardin\, CF Schmidt\, FC MacKi
 ntosh\, Science\, 315:370 (2007).\n2. FC MacKintosh and AJ Levine\, Phys R
 ev Lett\, 100:018104 (2008).\n3. CP Brangwynne\, FC MacKintosh\, DA Weitz\
 , PNAS\, 104:16128 (2007).\n4. CP Brangwynne\, GH Koenderink\, FC MacKinto
 sh\, DA Weitz\, J Cell Biology\, 183: 583-587 (2008).\n
LOCATION:Pippard Lecture Theatre\, Cavendish Laboratory
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