Fig. 2. Forces during virus uptake from the ventral cell side exceed biotin-neutravidin unbinding force.
a Schematic of a cell tearing off a biotin-neutravidin surface-bound virus particle. b Immunostaining for viral infection in HeLa cells (green, virus factories) upon tearing off biotin-neutravidin bound reovirus particles (magenta) from the surface. Arrowheads point towards regions where cells removed viruses completely from the surface. Scale bars, 50 and 10 µm in zoom-in. c Confocal time-lapse images of a HeLa cell (transmission) spreading and tearing off Alexa647-labeled reovirus particles (magenta) from the biotin-neutravidin surface with the cell outline at t0 + 30 min defining the region of interest (ROI). Scale bar, 10 µm. d Normalized number of virus particles over time either in the ROI under HeLa cells or in a control region outside cells. Data are represented as mean ± s.e.m. and fitted with two-phase decay or single exponential decay functions for ROI under cells and outside cells, respectively. e Fitting parameters a, the fraction, and koff, the off rate of particles being actively removed by cells or detaching outside cells. (n = 44 cells with a total of 5598 viruses and 10 control regions with 6892 total viruses from seven technical replicates. Box-plots represent median ± 95% CI with whiskers to the min and max values, ****P < 0.0001 according to unpaired two-tailed Mann–Whitney test). Source data are provided as a source data file.