ADAM7 Is Associated with Epididymosomes and Integrated into Sperm Plasma Membrane

Abstract

During epididymal transit, mammalian sperm acquire se-lected proteins secreted by the epididymis. We previously showed that a disintegrin and metalloprotease (ADAM) 7 is expressed specifically in the epididymis and transferred to the sperm surface during epididymal transit. Here, we show that mouse ADAM7 secreted to the epididymal lumen is associated with membranous vesicles known as epididy-mosomes. Furthermore, we found that ADAM7 can be trans-ferred directly from epididymal vesicles to sperm and that it is an integral plasma membrane protein in sperm. Thus, our study provides new information regarding the unique mode of secretion and interaction of ADAM7 during the epidi-dymis-to-sperm transfer process.