Fig 1: The degradation of PRKAR1 is dependent on the sperm proteasome. Total protein extracts were obtained from sperm incubated at different times with 0.1% DMSO or for 60 min with 10 µM epoxomicin (Epox). (A) The level of PRKAR1 was detected by Western blot using an anti-PRKAR1 antibody. (B) For the densitometric analysis, ß-tubulin was used as a loading control. Bars represent the mean ± S.E.M of seven different experiments. Different letters indicate statistically significant differences (p < 0.01) between groups. (C–F) For subcellular localization of PRKAR1, sperm were incubated under capacitation conditions for 1 min. Then, the cells were fixed and labeled with a primary anti-PRKARI antibody (D, red) and with Hoechst (E, blue). DIC: differential interference contrast (A). Merge: merged image of PRKAR1 and Hoechst (F; red and blue).