Cytoskeletal Mechanics and Dynamics

We will discuss some concepts, models, equations and experimental techniques relating to the study of cytoskeletal mechanics and dynamics.

Material and lectures by Chaitanya A. Athale

This is a five-lecture mini series on the Biophysics of the Cytoskeleton.

1. Mechanics of the cytoskeleton

Here we will be introducing the cytoskeleton in eukaryotes and prokaryotes, concepts of mechanics of springs and beams and how they relate to the cytoskeleton. We will specifically deal with some mechanical properties of actin. Some of the material concerns experimental methods used to measure the mechanics. Quiz questions will follow relating to (a) concepts, (b) models for mechanics and sums and (c) understanding of experimental measurement methods.

Video links

  1. Lec 01:
    Introduction and size and time scales
  2. Lec 02:
    Equilibrium mechanics and force generation
  3. Lec 03
    Mechanics of springs, equilibrium and force-spectroscopy
  4. Lec04
    Part 1 Mechanics of beams

2. Dynamics of the cytoskeleton

    In this second part we will consider a rate-equation formalism, as background to arriving at a simple biophysical model of processes governed by rate equations (ODEs). This will lead us to the ideas that cytoskeletal filaments are dynamic. Using the simplest possible model of dynamics we will determine average and population properties. We end with the idea of concentration dependence of polymerization and treadmilling.

    Video links:

  1. Part 2: Introduction to rate-equations
  2. Lec05
    Polymerization models: simple, asymmetry and ATP difference and thinking of Treadmilling in terms of kinetics. This lecture also has an associated PDF of the notes [here].

Reading biophysics

Reading material

(A) Textbooks

1) Phillips, et al. Physical Biology of the Cell. Garland Press, USA.

2) David Boal (2012) Mechanics of the Cell (2nd Edn.). Cambridge Univ. Press, UK

(B) Mechanics of cytoskeleton

1) Jie Zhu (2008) Force Generation by Actin Polymerization: Nanoscale to Microscale. Zhu, Jie. Washington University in St. Louis, ProQuest Dissertations Publishing, 2008. 3316702. https://search.proquest.com/docview/304442736

2) Athale C.A. (2011) Modelling the Spatial Pattern Forming Modules in Mitotic Spindle Assembly. In “Understanding the Dynamics of Biological Systems: Lessons Learned from Integrative Systems Biology” (Eds. Werner Dubitzky, Jenny Southgate, Hendrik Fuss).

3) Brangwynne et al. (2006) Microtubules can bear enhanced compressive loads in living cells because of lateral reinforcement. J Cell Biol (2006) 173 (5): 733–741. https:// rupress.org/jcb/article/173/5/733/44314/Microtubules-can-bear-enhanced-compressive- loads

4) P A Janmey, U Euteneuer, P Traub, M Schliwa (1991) Viscoelastic properties of vimentin compared with other filamentous biopolymer networks. J Cell Biol (1991) 113 (1): 155–160

5) P. A. Janmey (1991) A torsion pendulum for measurement of the viscoelasticity of biopolymers and its application to actin networks. J. Biochem. Biophys. Meth.

(C) Dynamics of cytoskeleton

1) Hasson et al. (1996) The photoisomerization of retinal in bacteriorhodopsin: Experimental evidence for a three-state model. PNAS

2) Patricia Wadsworth, Alexey Khodjakov (2004) E pluribus unum: towards a universal mechanism for spindle assembly. Tr. Cell Biology Volume 14, Issue 8, p413–419

3) Juliet Lee & Ken Jacobson (1997) The composition and dynamics of cell-substratum adhesions in locomoting fish keratocytes. J. Cell Sci. 110: 2833.

4) Kirschner & Mitchison (1986) Beyond self-assembly: From microtubules to morphogenesis. Cell 45: 392.

5) Padinhateeri R. et al. (2012) Random hydrolysis controls the dynamic instability of microtubules. Biophys. J. 102: 1274.

Last updated: 19-Mar-2021, Chaitanya A. Athale