Active Contraction of Microtubule Networks
We discovered that networks composed of stabilized microtubules in Xenopus oocyte extract undergo a spontaneous contraction on the millimeter length scale, due to the clustering of microtubule minus ends by the motor protein dynein. In collaboration with Michael Shelley and Sebastian Fürthauer at NYU, we developed an Active Fluid model that can quantitatively describe the contraction process.
PJ Foster, S Fürthauer, MJ Shelley, DJ Needleman, “Active contraction of microtubule networks”, eLife 2015;4:e10837; doi:10.7554/eLife.10837
PJ Foster*, W Yan*, S Fürthauer, MJ Shelley, DJ Needleman, "Connecting macroscopic dynamics with microscopic properties in active microtubule network contraction", New J. Phys. 2017;
doi:10.1088/1367-2630/aa9320 (* denotes co-first authors)
Collective Organization of Microtubules and Motors
In vitro systems of purified microtubules and motor proteins offer a greater degree of biochemical control compared with living systems. Can bulk microtubule network contractions be recapitulated with purified motors? In collaboration with Richard McKenney at UC Davis and Claire Walczak at IU we're studying collective behaviors of microtubules and motors proteins.
R Tan, PJ Foster, DJ Needleman, RJ McKenney, "Cooperative Accumulation of Dynein-Dynactin at Microtubule Minus-Ends Drives Microtubule Network Reorganization", bioRxiv 2017; doi:10.1101/140392 submitted
Bayesian Analysis of FLIM Data
Fluorescence Lifetime Imaging Microscopy (FLIM) is a spectroscopic method where changes in the lifetime of a fluorophore are used to infer changes in the fluorophore's local environment. How can one cope with noisy FLIM data? One approach is to use Bayesian inference to combine measured data with knowledge about the system. I helped to develop and test a FLIM analysis technique based on Bayesian statistics, which can be used to accurately infer fluorescence decay parameters in noisy regimes. This approach was then used to develop a technique to measure polymer assembly in cells and cell extracts.
B Kaye*, PJ Foster*, TY Yoo*, DJ Needleman, "Developing and Testing a Bayesian Analysis of Fluorescence Lifetime Measurements",PLoS ONE 2017;12(1);e0169337;
doi:10.1371/journal.pone.0169337 (* denotes co-first authors)
B Kaye, TY Yoo, PJ Foster, CH Yu, DJ Needleman, "Bridging length scales to measure polymer assembly", Mol. Biol. Cell 2017; 28(10); 1379-1388; doi:10.1091/mbc.E16-05-0344
Spindle Dynamics and Organization
Spindles are biochemically complex environments where many different kinds of proteins and complexes act in concert to organize dynamic microtubules. What framework can be used to understand the collective effects of these biochemical interactions and to understand effects on the spindle scale in terms of the interactions between individual components?
B Kaye, O Steihl, PJ Foster, MJ Shelley, DJ Needleman, S Fürthauer, "Measuring and modeling polymer gradients argues that spindle microtubules regulate their own nucleation", arXiv 2017; arXiv:1710.08405 [q-bio.SC] submitted