Sperm-egg fusion: events at the plasma membrane.
Sperm-egg fusion is a cell-cell membrane fusion event essential for the propagation of sexually reproducing organisms. In gamete fusion, as in other fusion events, such as virus-cell and intracellular vesicle fusion, membrane fusion is a two-step process. Attachment of two membranes through cell-surface molecules is followed by the physical merger of the plasma membrane lipids. Recent progress has demonstrated an essential role for an oocyte tetraspanin, CD9, in mouse sperm-egg fusion, and a specific molecular site crucial for CD9 function has been identified. Absence of glycosylphosphatidylinositol-anchored proteins on the oocyte surface also results in loss of oocyte fusion competence in this gamete. These discoveries provide a strong starting point for the identification of additional proteins that have roles in sperm-egg fusion.
Stein
Kathryn K
KK
Section of Molecular and Cellular Biology, School of Medicine, University of California Davis, Davis, CA 95616, USA.
Primakoff
Paul
P
Myles
Diana
D
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D002462:Cell Membrane / Q000502:physiology*; D005306:Fertilization; D006801:Humans; D008297:Male; D008561:Membrane Fusion; D008562:Membrane Glycoproteins / Q000378:metabolism; D010063:Ovum; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa; D060245:Tetraspanin 29
D015703:Antigens, CD; C554869:CD9 protein, human; C554870:Cd9 protein, mouse; D008562:Membrane Glycoproteins; D060245:Tetraspanin 29