In summary, this study analyses the changes in the concentration and localization of the actin filament-severing protein scinderin, during testicular development, and in spermatozoa during and following the epididymal transit. Immunoblot analyses showed one band at 80 kDa in chromaffin cells, fetal and adult tubules, interstitial cells, aorta and vena cava, and spermatozoa. Scinderin immunoreactiv-ity was associated with a region corresponding with the subacrosomal space and with the acrosome in the spermatids. In epididymal spermatozoa, scinderin was located in the anterior acrosome and in the equatorial segment, but in ejaculated spermatozoa, the protein appeared in the acro-some and the post-equatorial segment of the head. In Sertoli cells, the protein was detected near the cell surface during all the stages of the cycle and within the cytoplasm, where it accumulated near the base in a stage-specific manner.
In the epididymis, scinderin was also localized next to the surface of the cells; in the tail (cauda), it collected near the base of the principal cells. The results suggest that scinderin may be involved in actin remodeling in Sertoli cells and epididymal cells, where it may play a role in the control of the state of perijunctional actin and contribute to the regulation of tight junctional permeability, and in germ cells, where it may assist in shaping the developing acrosome and influence the fertility of the spermatozoa.