Fig. 6.

Actin and myosin inhibitors block the relocation of Izumo. (A) Anti-Izumo fluorescent staining of WT sperm incubated for 1 hour in media that support capacitation either in the presence or absence of 5 μM latrunculin A. Izumo immunoreactivity examples of intact sperm (no treatment) and Ca²⁺-ionophore-induced acrosome-reacted sperm are shown. (B) WT sperm were incubated in capacitating medium containing increasing concentrations of latrunculin A, ML-7, blebbistatin or H89 for 1 hour. Then, 5 μM A23187 was added and the sperm incubated for 30 additional minutes. The sperm were then washed, fixed and anti-Izumo immunofluorescence analysis was conducted as described in the Materials and Methods. Points represent the percentage of acrosome-reacted sperm presenting posterior head Izumo staining. Results represent the mean ± s.d. of at least three independent experiments in which 200 sperm were counted per condition.