RT Journal Article
SR Electronic
T1 Quantification of nuclear transport in single cells
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 001768
DO 10.1101/001768
A1 Lucía Durrieu
A1 Rikard Johansson
A1 Alan Bush
A1 David Janzén
A1 Martin Gollvik
A1 Gunnar Cedersund
A1 Alejandro Colman-Lerner
YR 2014
UL http://biorxiv.org/content/early/2014/01/11/001768.abstract
AB Regulation of nuclear transport is a key cellular function involved in many central processes, such as gene expression regulation and signal transduction. Rates of protein movement between cellular compartments can be measured by FRAP. However, no standard and reliable methods to calculate transport rates exist. Here we introduce a method to extract import and export rates, suitable for noisy single cell data. This method consists of microscope procedures, routines for data processing, an ODE model to fit to the data, and algorithms for parameter optimization and error estimation.Using this method, we successfully measured import and export rates in individual yeast. For YFP, average transport rates were 0.15 sec-1. We estimated confidence intervals for these parameters through likelihood profile analysis. We found large cell-to-cell variation (CV = 0.79) in these rates, suggesting a hitherto unknown source of cellular heterogeneity. Given the passive nature of YFP diffusion, we attribute this variation to large differences among cells in the number or quality of nuclear pores.Owing to its broad applicability and sensitivity, this method will allow deeper mechanistic insight into nuclear transport processes and into the largely unstudied cell-to-cell variation in kinetic rates.