Signal Transduction in Mammalian Spermatozoa

Kopf, Gregory S.; Kaláb, Petr; Leclerc, Pierre; Ning, Xiaoping; Pan, Dieyun; Visconti, Pablo E.

doi:10.1007/978-3-662-22189-1_8

Cited by 19 publications

(17 citation statements)

References 77 publications

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“…It has recently been shown that acrosomal exocytosis of human spermatozoa can be studied in vitro using small volumes of solubilized human zonae pellucidae and that G proteins are involved as mediators [Franken et al, 1996]. This confirms previous studies that demonstrated the involvement of heterotrimeric G proteins in the induction of the acrosome reaction in other species [Kopf, 1990;Nixon et al, 2001;Wassarman and Litscher, 2001].…”

Section: Clinical Aspectssupporting

confidence: 79%

Molecular Basis of Human Sperm-Zona pellucida Interaction

Oehninger¹

2000

Cells Tissues Organs

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The recognition of carbohydrate sequences by complimentary receptors has been shown to be a critical factor in gamete interaction in many different animal species. We have proposed the hypothesis that, in the human, sperm binding to the zona pellucida requires a ‘selectin-like’ interaction. We have used the hemizona assay (a unique internally controlled bioassay that evaluates tight binding of human sperm to the homologous zona pellucida) and advanced methods of carbohydrate analysis to test this hypothesis. We provide compelling evidence that demonstrates that oligosaccharide recognition is also required for specific, tight human gamete binding. Hapten inhibition tests, zona pellucida lectin-binding studies and removal/modification of functional carbohydrates by chemical and enzymatic methods provide evidence for the involvement of defined carbohydrate moieties in initial binding. Our studies suggest the existence of distinct zona-binding proteins on human sperm that can bind to selectin ligands. Additionally, results suggest a possible convergence in the types of carbohydrate sequences recognized during initial human gamete binding and immune/inflammatory cell interactions. Full characterization of the glycoconjugates that manifest selectin-ligand activity on the human zona pellucida will allow for a better understanding of human gamete interaction in physiological and pathological situations.

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Section: Clinical Aspectssupporting

confidence: 79%

Molecular Basis of Human Sperm-Zona pellucida Interaction

Oehninger¹

2000

Cells Tissues Organs

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“…Models of the signal transduction pathways involved in the acrosome reaction have been proposed (Florman et al, 1989;Kopf, 1990;Kopf and Gerton, 1991;Zaneveld et al, 1991). There are a number of signal transduction components such as cAMP, protein kinase C, Ca 2+ -calmodulin kinase, tyrosine kinases, inositol phosphates and Gi-like protein in human spermatozoa.…”

Section: Discussionmentioning

confidence: 98%

Andrology: Disordered acrosome reaction of spermatozoa bound to the zona pellucida: a newly discovered sperm defect causing infertility with reduced sperm-zona pellucida penetration and reduced fertilization in vitro

1994

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It is believed that during the process of human fertilization, acrosome-intact spermatozoa bind to the surface of the zona pellucida which triggers the acrosome reaction and the enzymes released facilitate sperm penetration through the zona pellucida. We describe here reduced frequency of the acrosome reaction on the zona pellucida as a cause of infertility in 10 couples with long durations of infertility (average 6 years) and low (< 15%, n = 3) or zero (n = 7) fertilization rates in vitro. Sperm concentration, motility, velocity (Hamilton-Thorn), morphology and DNA normality were within the normal range in all the patients. Electron microscopy of spermatozoa did not reveal any specific ultrastructural defects. All couples were negative for antisperm antibodies by immunobead tests. Oocytes from other patients which failed to fertilize in in-vitro fertilization and normal donor spermatozoa were used as controls for sperm-zona pellucida binding and penetration experiments. Acrosome status of spermatozoa bound to the zona pellucida was assessed with a fluorescent lectin and electron microscopy. The mean number of spermatozoa bound to the zona pellucida was not significantly different between patients and controls. However, the acrosome reaction of spermatozoa bound to the zona pellucida after 2 h incubation was significantly lower (P < 0.001) in the patients (mean 5%, range 0-16) than in the controls (mean 68%, range 44-96). No zona pellucida (out of 40) was penetrated by patient spermatozoa whereas most (39/40) zonae were penetrated by control spermatozoa (average 27 spermatozoa/four zonae pellucidae).(ABSTRACT TRUNCATED AT 250 WORDS)

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“…Intracellular signalling mechanisms known to be under G protein control in somatic cells are believed to regulate various sperm functions. Recent reports gave evidence that in various mammalian sperm reactions in response to the extracellular environment, G proteins occupy critical steps in signal transduction (Kopf, 1990). Spermatozoa from various species were found to contain 41-kDa pertussis toxin-sensitive u-subunits of G proteins as well as immunologically identified u-subunits (Bently et al, 1986;Kopf et al, 1986).…”

Section: Introductionmentioning

confidence: 96%

Identification of heterotrimeric G proteins in human sperm tail membranes

Hinsch

Schwerdel

Habermann

et al. 1995

Molecular Reproduction Devel

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Heterotrimeric G proteins play important roles as signal transducing components in various mammalian sperm functions. We were interested in the distribution of G proteins in human sperm tails. Prior to membrane preparation, spermatozoa were separated from contaminating cells which are frequently present in human ejaculates. Enriched human sperm tail membranes were generated by using hypoosmotic swelling and homogenization procedures. Antisera against synthetic peptides were used to identify G proteins in immunoblots. AS 8, an antiserum directed against an amino acid sequence that is found in most G protein alpha-subunits, and A 86, which detects all known pertussis toxin-sensitive alpha-subunits, reacted specifically with a 40-kDa protein. Antisera against individual G protein alpha-subunits failed to detect any specific antigens in enriched tail membranes. AS 36, recognizing the beta 2-subunit of G proteins, identified a 35-kDa protein in sperm tail membranes. Antisera against the 36-kDa beta 1-subunit did not detect any relevant proteins in the membrane fraction. Neither G protein alpha-subunits nor G protein beta-subunits were found in the cytosol. ADP ribosylation of spermatozoal membrane or cytosolic proteins revealed no pertussis toxin-sensitive alpha-subunits. However, membrane preparations of nonpurified human spermatozoa contained alpha i2 subunits, as shown immunologically and by ADP ribosylation; they most probably derived from somatic cells which are frequently present in human ejaculates. Our results stress the fact that spermatozoa need to be purified before sperm membrane preparation to avoid misinterpretations caused by contaminating cells. Furthermore, we suggest that G proteins in membranes of human sperm tails belong to a novel subtype of G protein alpha-subunits; the putative beta-subunit was identified as a beta 2-subunit.

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Signal Transduction in Mammalian Spermatozoa

Cited by 19 publications

References 77 publications

Molecular Basis of Human Sperm-Zona pellucida Interaction

Molecular Basis of Human Sperm-Zona pellucida Interaction

Andrology: Disordered acrosome reaction of spermatozoa bound to the zona pellucida: a newly discovered sperm defect causing infertility with reduced sperm-zona pellucida penetration and reduced fertilization in vitro

Identification of heterotrimeric G proteins in human sperm tail membranes

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