Role of Egg Sulfolipidimmobilizing Protein 1 on Mouse Sperm-Egg Plasma Membrane Binding1

Abstract

We have shown that sperm sulfolipidimmobilizing protein 1 (SLIP1, molecular mass of 68 kDa), a sulfogalactosylglycerolipid (SGG)-binding protein, is significant in sperm-zona pellucida (ZP) interaction. The objective of this study was to localize SLIP1 on the egg and determine its role in gamete interaction. Immunofluorescence and immunoprotein A gold electron microscopy localized SLIP1 to the egg plasma membrane. In vitro gamete binding, using zona-free eggs preincubated with antiSLIP1 Fab before coincubation with sperm, showed a significant, dose-dependent decrease in sperm-egg plasma membrane binding. Similar results were obtained when affinity-purified antiSLIP1 IgG was used for egg pretreatment. The significance of egg SLIP1 in sperm-egg plasma membrane binding was further demonstrated by a decrease (36-52%) in in vitro fertilization when zona-intact eggs were pretreated with antiSLIP1 IgG. Since SLIP1 has been shown to bind SGG in vitro, we investigated the possibility that sperm SGG may participate in sperm-egg plasma membrane binding through egg SLIP1. Pretreatment of sperm with antiSGG Fab prior to coincubation with zona-free eggs resulted in a dose-dependent decrease in sperm-egg plasma membrane binding. Collectively, these findings strongly suggest a role for egg SLIP1 in sperm-egg plasma membrane interaction, which may be through its binding to sperm SGG.

Arylsulfatase A deficiency causes seminolipid accumulation and a lysosomal storage disorder in Sertoli cells

“…In addition, SGG on the acrosome-reacted sperm head plays roles in sperm-egg plasma membrane interaction ( 44 ). SGG is also an integral component of sperm head…”

Anti-SLIP1-reactive proteins exist on human spermatozoa and are involved in zona pellucida binding

“…Subsequently, it antiserum (IgG) generated against rat serum albumin (RSA), antiwas shown that a crude extract of SLIP1 can be prepared by RSA, were purchased from Organon Teknika Inc. (Scarborough, treating intact testicular cells or gametes (Law et al, 1988;ON, Canada). A goat anti-rabbit immunoglobulin conjugated with Tanphaichitr et al, 1993;Ahnonkitpanit et al, 1999) proteins from intact cells (Carter and Hakomori, 1977).…”

“…Previously described procedures were used to prepare IgG fraction Lingwood and his associates have further demonstrated that from anti-SLIP1 antiserum (Tanphaichitr et al, 1993), to formylate rat testis SLIP1 can be purified from its AES crude extract to anti-SLIP1 IgG to reduce non-specific binding to spermatozoa (Lingwood, 1985), to generate affinity-purified anti-SLIP1 IgG a single 68 kDa band on sodium dodecyl sulphate-polyacryl- (Ahnonkitpanit et al, 1999), and to conjugate a fluorochrome, Cy3…”

Identification of the Sea Urchin 350-kDa Sperm-binding Protein as a New Sialic Acid-binding Lectin That Belongs to the Heat Shock Protein 110 Family

“…In mouse fertilization, the importance of the major glycolipid, sulfogalactosylglycerolipid (SGG) 1 on the sperm surface has been shown, because a SGG-recognizing protein, sulfolipid immobilizing protein 1 (SLIP1), is present on both egg and sperm surfaces (3,8). Egg SLIP1 is suggested to be involved in sperm-egg plasma membrane binding through its binding to SGG (9). Recently, a liposome containing SGG has been shown to bind the zona pellucida, the egg extracellular glycoprotein matrix, suggesting the presence of another binding counterpart to SGG in the zona components of the mouse (10).…”