Statistical analyses were performed using GraphPad Prism 6. The type and number of replicates, the statistical test used, and the test results are described in the figure legends. All statistical tests employed were two-tailed. Unless stated otherwise in the figure legends, all graphical data are presented as mean±s.e.m. No experimental samples were excluded from the statistical analyses. Sample size was not pre-determined through power calculations, and no randomization or investigator blinding approaches were implemented during the experiments and data analyses. When representative results are presented, the experiments were reproduced in at least two independent cultures.
