Sperm plasma membrane

About: Sperm plasma membrane is a research topic. Over the lifetime, 1016 publications have been published within this topic receiving 49964 citations.

Involvement of Wheat Germ Agglutinin (WGA)-Binding Protein in the Induction of the Acrosome Reaction of the Sea Urchin, Strongylocentrotus intermedius. II. Antibody against WGA-Binding Protein Induces the Acrosome Reaction: WGA-binding protein/sea urchin/sperm/acrosome reaction

Abstract: We obtained a polyclonal antibody against the WGA-binding protein (WGAbp) of Strongylocentrotus intermedius sperm, which is a membrane glycoprotein of 260 kD under non-reducing condition Anti-WGAbp antibody induced increases in both intracellular Ca2+ ([Ca2+]i) and intracellular pH (pHi), resulting in the onset of the AR The increases in [Ca2+]i and pHi required extracellular Ca2+ and Na+, respectively, and were suppressed by the pretreatment with WGA, resulting in the inhibition of the AR Anti-WGAbp antibody-induced AR was inhibited also by lowered extracellular pH elevated K+, removal of Na+ from seawater and the treatment with verapamil, a Ca2+ channel inhibitor These inhibitory conditions are identical with those of the egg jelly-induced AR Monovalent Fab fragments from anti-WGAbp antibody also induced the AR at relatively high concentration These results suggest that the WGAbp on the sperm plasma membrane is involved in the regulation of Ca2+ influx and Na+/H+ exchange associated with the AR of S intermedius sperm It is a strong candidate for the receptor of the AR-inducing substance in the egg jelly

Effect of Glutathione on Sperm Quality in Guanzhong Dairy Goat Sperm During Cryopreservation

Abstract: In the process of cryopreservation of dairy goat semen, it will face many threats such as oxidative damage, which will affect the motility and plasma membrane function of sperm. As an endogenous antioxidant in animals, glutathione(GSH) can significantly improve the quality of thawed sperm when added to the frozen diluent of semen of pigs and cattle. In this study, different concentration gradients of GSH[0mmol/L(control), 1mmol/L, 2mmol/L, 3mmol/L, 4mmol/L] were added to the frozen diluent of Guanzhong dairy goat semen. By detecting the sperm motility parameters, acrosome intact rate and plasma membrane intact rate after thawing, the effect of GSH on the cryopreservation of dairy goat semen was explored. Sperm motility parameters were measured with the computer-aided sperm analysis(CASA) system (total power, TM; forward power, PM; linearity, LIN; average path speed, VAP; straight line speed, VSL; curve speed, VCL; beat cross frequency, BCF.). The sperm acrosome integrity rate after thawing was detected by a specific fluorescent probe (isothiocyanate-la beled peanut agglutinin, FITC-PNA), and the sperm plasma membrane integrity rate after thawing was detected by the hypotonic sperm swelling (HOST) method. Reactive oxygen species (ROS) kit, malondialdehyde (MDA) kit, superoxide dismutase (SOD) kit, glutathione peroxidase (GSH-PX) kit were used to detect various antioxidant indicators of thawed sperm. In vitro fertilization experiment was used to verify the effect of adding glutathione on sperm fertilization and embryo development. The results showed that when the concentration of glutathione was 2mmol/l, the sperm viability, plasma membrane intact rate and acrosome intact rate were the highest after thawing, reaching 62.14%, 37.62% and 70.87% respectively, and they were all significantly higher. In terms of antioxidant indexes; the values of SOD and GSH-PX were 212.60 U/mL and 125.04 U/L respectively, which were significantly higher than those of the control group; The values of ROS and MDA were 363.05 U/mL and 7. 02 nmol/L respectively, which were significantly lower than the control group. The addition of 2mmol/L glutathione significantly improves the fertilization ability of sperm. In short, adding 2mmol/l glutathione to the semen diluent can improve the quality of frozen Guanzhong dairy goat sperm.

Redistribution of soluble N-ethylmaleimide-sensitive-factor attachment protein receptors in mouse sperm membranes prior to the acrosome reaction.

Abstract: Formation of complexes between soluble N-ethylmaleimide-sensitive-factor attachment protein receptor (SNARE) proteins on opposing membranes is the minimal requirement for intracellular membrane fusion. The SNARE, syntaxin 2, is found on the sperm plasma membrane and a second SNARE, vesicle associated membrane protein 2 (VAMP2, also known as synaptobrevin 2, SYB2), is on the apposing outer acrosomal membrane. During the acrosome reaction, the outer acrosomal membrane fuses at hundreds of points with the plasma membrane. We hypothesized that syntaxin 2 and VAMP2 redistribute within their respective membranes prior to the acrosome reaction to form trans-SNARE complexes and promote membrane fusion. Immunofluorescence and superresolution structured illumination microscopy were used to localize syntaxin 2 and VAMP2 in mouse sperm during capacitation. Initially, syntaxin 2 was found in puncta throughout the acrosomal region. At 60 and 120 min of capacitation, syntaxin 2 was localized in puncta primarily in the apical ridge. Although deletion of bicarbonate during incubation had no effect, syntaxin 2 puncta were relocated in the restricted region in less than 20% of sperm incubated without albumin. In contrast, VAMP2 was already found in puncta within the apical ridge prior to capacitation. The puncta containing syntaxin 2 and VAMP2 did not precisely co-localize at 0 or 60 min of capacitation time. In summary, syntaxin 2 shifted its location to the apical ridge on the plasma membrane during capacitation in an albumin-dependent manner but VAMP2 was already localized to the apical ridge. Puncta containing VAMP2 did not co-localize with those containing syntaxin 2 during capacitation; therefore, formation of trans-SNARE complexes containing these SNAREs does not occur until after capacitation, immediately prior to acrosomal exocytosis.

La capacitation in vitro

Abstract: Capacitation is a prerequisite for mammalian spermatozoa to fertilize oocytes. Lipids play a crucial role in the structural and functional organization of sperm plasma membrane. Lipid and membrane protein ordering changes dramatically during sperm capacitation but the resulting effects differ according to the regions of the sperm head. Lipids modifications are mainly characterized by a cholesterol efflux, dynamic cholesterol redistribution in particular in the apical zone of the head and also a phospholipids reorganization resulting to the scramblase activation. The existence of lipids ordered microdomains (lipid rafts) has been recently observed in sperm membranes. These lipid and membrane protein movements are believed to play a role in modulating signaling pathways mainly, the AMPc/PKA and ERK pathways. One of the early key events is the activation of adenylate cyclase by high levels of bicarbonate. All these pathways lead finally to the phosphorylation of Tyr-proteins. But capacitation seems to be more complex with the contribution of other kinases (from the PI3K/Akt pathway and phosphotyrosine kinases) towards the phosphorylation of other Ser/Thr and Tyr proteins. The reactive oxygen species (ROS) seem to be important in the control of mechanisms involved in capacitation.

Characterization of the 84-kDa protein with ABH activity in human seminal plasma.

Abstract: In order to identify the blood group substance detected on the sperm plasma membrane (SPM), a plasma membrane preparation was obtained from the sperm soluble protein and then injected into a rabbit to produce an anti-SPM antibody. An anti-SPM antibody-binding affinity column specifically bound 6 polypeptides with molecular masses of 135 kDa, 84 kDa, 78 kDa, 67 kDa, 54 kDa and 20 kDa from seminal plasma. Among these polypeptides, the 84-kDa protein (p 84) showed ABH antigenic activity upon immunoblotting. When viable, motile sperm were incubated at 37 degrees C in the culture medium, they became capacitated and p 84 was released into the medium from the sperm surface after 3 h of incubation, indicating that p 84 is a sperm-coating antigen. Immunoblotting of sexual glands revealed that this protein is originated from the seminal vesicle. Its immunological properties were similar to those of lactoferrin. When seminal plasma was immunoprecipitated with anti-human lactoferrin antiserum, the immunoprecipitates contained both p 84 and ABH antigenic activity. The amino acid sequence of the N-terminus of p 84 was determined to be: G-R-?-R-?-S-V-Q-W-?-A-V-S-Q-P-E-A-D-K-?-F-Q-W-Q-R-N-M-R-K-V-R-G-P-?-V or P-S?-?-I. Although this sequence is highly homologous to lactoferrin, the 18th residue is different (p 84, D; lactoferrin, T). These data suggest that p 84 is the protein which has not been identified and bears the ABH antigen. A sandwich ELISA using anti-SPM antibody was able to bind p 84 and allowed determination of the ABO blood type of semen and saliva, but detected no ABH antigenic activity in breast milk, vaginal fluid, erythrocytes, serum or urine. These results suggest that p 84 is the best candidate for ABO blood typing of semen when contaminating vaginal fluid is present.