Calcium-Dependent Actin Filament-Severing Protein Scinderin Levels and Localization in Bovine Testis, Epididymis, and Spermatozoa(2)
Not everybody agrees on the precise location of actin in the germ cells, or on whether actin exists predominantly in a monomeric or filamentous state. Yet divergent views may not necessarily need to be contradictory. It is generally accepted that actin exists in equilibrium between G- and F-actin within the cell. The presence of higher amounts of one or the other form of actin in germ cells may reflect short-lived actions of actin-interacting proteins during the germ cell’s development and epididymal transit. Individual actions may appear conflicting among themselves, but taken together they show a logical progression of related events designed to meet specific physiological requirements. Buy Advair Diskus Online
It is to try to better understand the role of actin during germ cell development in the testis and maturation in the testicular excretory ducts that we elected to study the changes in the concentration and distribution of the actin filament-severing protein scinderin in the developing bovine testis and in the spermatozoa during and following their epididymal transit.
Scinderin has been reported typically in tissues demonstrating a high secretory activity including adrenal glands, pituitary, brain, testis, kidney, and salivary glands. In chromaffin cells of the adrenal glands, scinderin shows a cytoplasmic distribution as well as a subsurface localization that coincided with cortical actin. Scinderin severs F-actin in a Ca2+-dependent manner and possesses two Ca2+ binding sites. Furthermore, scinderin binds to phosphatidylinositol 4,5-bisphosphate (PIP2), suggesting the protein can interact with the plasma membrane via binding to this particular membranous phospholipid.
No studies have yet assessed scinderin expression and localization during testicular development or during the ep-ididymal transit of spermatozoa, two physiological conditions during which modifications of the actin cytoskeleton take place. The present study uses the bull as an animal model and reports the changes in the protein level and in the localization of scinderin in Sertoli cells, germ cells, and epididymal cells during testicular development and following epididymal transit of spermatozoa.