The human sperm equatorial segment: composition and roles in sperm function

Human sperm contain a unique membranous structure in the middle of the sperm head called the equatorial segment. This subcellular organelle is thought to have distinctive and essential functions in the intimate interactions between sperm and egg during fertilization.  Over the years, some components of the equatorial segment have been identified, but the organelle has not been purified or characterized as an integrated structure.  The details of its organization and function invite refined investigation.  Because it probably has essential but poorly understood roles in the continuity of our species, the sperm equatorial segment is a compelling focus for research.  Recent studies at Lehigh have shown that the enzyme SMALF [Sperm Membrane associated Alpha-L-Fucosidase] is enriched within the equatorial segment, and it has important roles in fertilization and early embryo development in animal systems.  Independent studies within our earlier collaboration here have also identified novel compounds, including fluorous surfactants, that may be useful for the selective extraction and chemical dissection of sperm.  We hope to use the distinctive tools at hand to advance insights into the structure and functions of the equatorial segment, potentially including subcellular fractionation and purification of this organelle.