(C) Average number, normalized on cell size, of EEA-1+ endosomes as in a. Results are the average ± SEM of three independent experiments for a total 4483 early endosomes in 18 siCTL cells (299 ± 33 endosomes per cell) and 2454 early endosomes in 13 siSTIM1 cells (189 ± 17 endosomes per cell) and analyzed by a two-tailed heteroscedastic Student's t-test, p≤ 0,01 **. 