USP8, a Regulator of Endosomal Sorting, Is Involved in Mouse Acrosome Biogenesis Through Interaction with the Spermatid ESCRT-0 Complex and Microtubules: USP8
The number and position of ubiquitin molecules bound to lysine residues of a target protein are, in fact, an important signal for directing the subcellular localization and intracellular traffic of the protein cargo, and the ubiquitin-specific proteases like USP8 are critical in defining the trimming of the ubiquitin moiety. canada health and care mall
Moreover, neurons and sperm possess additional, cell-specific vesicular organelles: the neuronal-signaling endosome and the sperm acrosome. The sperm acrosome is an acidic secretory vacuole, considered to be indispensable at fertilization, whose nature and origin, however, have not yet been clearly defined. Originally described as a modified lysosome,the acrosome has been then reported as a direct Golgi-derived secretory vesicle, and some studies have even argued against its lysosomal/endosomal origin. More recently, however, the concept of it being a Golgi-derived organelle has been revisited, and its lysosomal origin is being once again considered. Significantly, previously unidentified vesicle membrane proteins working at the plasma membrane/early endosome level, as AFAF and DYDC1, or as a regulator of lysosomal delivery, as SPE-39, have been recently shown to be involved in acrosomogenesis. So, at present, experimental evidence indicates that there are at least two sources of vesicular transport to the developing acrosome, one derived from the Golgi and one from the plasma membrane, as already suggested when the outer acrosomal membrane was proposed as another plasma membrane. The genesis of the acrosome remains an issue of some importance to be clarified in its details; in mammals, spermatozoa lacking a true acrosome are infertile. In this context, we have addressed questions related to mouse USP8 and the early endosome/vesicular system in spermatogenic cells with particular attention to differentiating spermatids, the cells where acrosomogenesis takes place.