Role of seminal plasma phospholipid-binding proteins in sperm membrane lipid modification that occurs during capacitation.
Bovine seminal vesicles secrete a family of similar proteins designated BSP-A1, BSP-A2, BSP-A3 and BSP-30-kDa (collectively called bovine seminal plasma (BSP) proteins). The biochemical properties of these proteins are well documented and considerable progress has been made concerning their biological role. At ejaculation these BSP proteins bind to the sperm surface. The binding sites on the sperm surface have been identified as choline phospholipids (specifically phosphatidylcholine (PC), phophatidylcholine plasmalogen (PC plasm) and sphingomyelin (SPM)) composed of sperm plasma membrane. Our previous studies have shown that the BSP proteins interact specifically with heparin and high-density lipoproteins (HDL), the capacitation factors in bovine. In addition, we have shown that the BSP proteins potentiate epididymal sperm capacitation induced by heparin and HDL. Recently, we showed that the BSP proteins stimulated cholesterol and phospholipid efflux from the sperm membrane. Furthermore, the lipid efflux from sperm is dependent on BSP protein concentration and duration of incubation. The loss of membrane cholesterol is an important step in the capacitation process. These results together indicate that BSP proteins play an important role in sperm membrane lipid modification events that occur during sperm capacitation.
Manjunath
Puttaswamy
P
Department of Medicine, University of Montreal and Guy-Bernier Research Center, Maisonneuve-Rosemont Hospital, 5415 Blvd. de L'Assomption, Montreal, Québec, Canada H1T 2M4. manjunap@medclin.umontreal.ca
Thérien
Isabelle
I
D000595:Amino Acid Sequence; D000818:Animals; D001693:Biological Transport, Active; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism; D004822:Epididymis / Q000166:cytology / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D010743:Phospholipids / Q000378:metabolism*; D029589:Seminal Plasma Proteins / Q000378:metabolism*; D029607:Seminal Vesicle Secretory Proteins / Q000737:chemistry / Q000378:metabolism; D013075:Sperm Capacitation / Q000502:physiology*; D013094:Spermatozoa / Q000378:metabolism*
C424322:BSP-30-kDa protein, Bos taurus; D008563:Membrane Lipids; D010743:Phospholipids; C424304:SVS8 protein, Bos taurus; D029589:Seminal Plasma Proteins; D029607:Seminal Vesicle Secretory Proteins; C424303:seminal vesicle secretory protein 109, Bos taurus; D002784:Cholesterol