Sperm are highly polarized cells, and their membranes can be categorized into different compartments. In intact sperm, the plasma membrane on the head surrounds the anterior acrosome, the equatorial segment, and the postacrosomal region. In the tail, the membrane covers the anterior part of the flagellum (midpiece) containing the mitochondria and the posterior portion of the tail (principal piece) containing the fibrous sheath surrounding the outer dense fibers [25] . These sperm compartments should be taken into account when the role of DRM proteins is analyzed; therefore, in this study we used antibodies against a subset of these proteins to investigate their localization in mouse sperm and their behavior during capacitation. Using filipin staining, the cholesterol-rich regions have been mapped to the plasma membrane overlaying the acrosome [5, 26, 27] . However, our findings indicate that proteins present in the light buoyant fractions, as well as other molecules known to distribute dynamically in membrane rafts, localized in multiple sperm compartments, including the anterior head, equatorial segment, cytoplasmic droplet, midpiece, and principal piece. When the behavior of these molecules during capacitation was studied, no changes were found in the tail-resident proteins. On the other hand, while some of the molecules in the head were lost, others change their immunofluorescence pattern; these changes were observed only in sperm that had undergone acrosomal exocytosis. IZUMO, present exclusively in the acrosomal region in intact sperm, spread to the post-and para-acrosomal regions of the sperm head in acrosome-reacted cells, while flotillin 2 (FLOT2), originally in the dorsal acrosome and midpiece, appeared in the equatorial segment. Considering that sperm acquire fusogenic capacity after the acrosome reaction, these changes in DRM-associated proteins could indicate their involvement in sperm-egg interaction.