Signal Transduction Mechanisms Regulating Sperm Acrosomal Exocytosis

Kopf, Gregory S.

doi:10.1016/b978-012311629-1/50008-5

Cited by 15 publications

(15 citation statements)

References 238 publications

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“…Instead, they proposed that a ''mechanosensory'' signal produced by the penetration of the sperm through the zona pellucida matrix is sufficient for inducing acrosomal exocytosis. These results are inconsistent with the ligand-receptor signal transduction model in acrosome exocytosis, supported by many observations that acid-solubilized ZP or purified ZP3 can stimulate acrosomal exocytosis (Bleil and Wassarman, 1980;Bleil and Wassarman, 1983;Kopf, 2002). From our perspective, any model for acrosomal exocytosis must take into account the microenvironment at the site of sperm-zona pellucida interaction, the capacitation state of the sperm, and the kinetics of acrosomal exocytosis compared to conditions utilizing native ZP.…”

Section: Role Of Calcium In Acrosomal Exocytosiscontrasting

confidence: 50%

Acrosomal exocytosis of mouse sperm progresses in a consistent direction in response to zona pellucida

Buffone

Rodríguez‐Miranda

Storey

et al. 2009

Journal Cellular Physiology

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Sperm acrosomal exocytosis is essential for successful fertilization, and the zona pellucida (ZP) has been classically considered as the primary initiator in vivo. At present, following what is referred to as primary binding of the sperm to the ZP, the acrosome reaction paradigm posits that the outer acrosomal membrane and plasma membrane fuse at random points, releasing the contents of the acrosome. It is then assumed that the inner acrosomal membrane mediates secondary binding of the sperm to the ZP. In the present work we used a live fluorescence imaging system and mouse sperm containing enhanced green fluorescent protein (EGFP) in their acrosomes. We compared the processes of acrosomal exocytosis stimulated by the calcium ionophore ionomycin or by solubilized ZP. As monitored by the loss of EGFP from the sperm, acrosomal exocytosis driven by these two agents occurred differently. When ionomycin was used, exocytosis started randomly (no preference for the anterior, middle or posterior acrosomal regions). In contrast, following treatment with solubilized ZP, the loss of acrosomal components always started at the posterior zone of the acrosome and progressed in an anterograde direction. The exocytosis was slower when stimulated with ZP and on the order of 10 sec, which is in accordance with other reports. These results demonstrate that ZP stimulates acrosomal exocytosis in an orderly manner and suggest that a receptor-mediated event controls this process of membrane fusion and release of acrosomal components. These findings are incorporated into a model.

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Section: Role Of Calcium In Acrosomal Exocytosiscontrasting

confidence: 50%

Acrosomal exocytosis of mouse sperm progresses in a consistent direction in response to zona pellucida

Buffone

Rodríguez‐Miranda

Storey

et al. 2009

Journal Cellular Physiology

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“…In mammalian reproduction, progesterone has been implicated to be involved in AR (reviewed by Calogero et al 2000), in human (Osman et al 1989, Baldi et al 1995, Patrat et al 2000, mouse (Melendrez et al 1994), stallion (Meyers et al 1995), golden hamster (Meizel et al 1990), dog (Sirivaidyapong et al 1999), goat (Somanath et al 2000 and boar (Jang & Yi 2002). Progesterone, by binding to a non-genomic mPR, has been reported to induce AR via intracellular signal transduction cascades (Kopf 2002). Parinaud & Milhet (1996) demonstrated that progesterone-induced AR may involve a cAMP-mediated pathway by showing that concentrations of cAMP increase in a Ca 2+ -dependent manner from human sperm.…”

Section: Discussionmentioning

confidence: 99%

“…Although the mechanism is poorly understood, the AR induced by progesterone is regulated by signal transduction processes upon progesterone binding onto a still unidentified mPR. This represents an integration between changes in ionic conductance and second messenger generation (Kopf 2002). Since the mPR has not been unequivocally identified yet from boar spermatozoa, here we report a 71 kDa sperm membrane protein as a novel putative non-genomic mPR in boar spermatozoa employing Western blot and ligand blot analyses.…”

Section: Introductionmentioning

confidence: 99%

Identification of a 71 kDa protein as a putative non-genomic membrane progesterone receptor in boar spermatozoa

Jang¹,

Yi²

2005

Journal of Endocrinology

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A putative non-genomic progesterone receptor was identified by Western blot analysis from the membrane fraction but not the cytosolic fraction of boar spermatozoa using monoclonal antibody (mAb) C-262. When the membrane and the cytosolic fractions of boar liver, kidney, uterus and spermatozoa were analyzed with mAb C-262, protein bands with molecular masses of 86 and 120 kDa were detected from the cytosolic fraction of the uterus, whereas a 71 kDa protein was detected from the membrane fraction of spermatozoa. Apparently, while the 86 and 120 kDa proteins from the uterus correspond to the genomic progesterone receptor isoforms A and B in boar, the 71 kDa protein of the sperm membrane fraction seems to be a novel membrane-associated progesterone receptor. Ligand blot assay of the membrane and the cytosolic fractions of boar spermatozoa performed with peroxidaseconjugated progesterone revealed that only the 71 kDa membrane protein binds specifically to progesterone, reinforcing the results obtained from the Western blot analysis. Also ligand blot assays performed in the presence of mAb C-262 demonstrated that mAb C-262 inhibited progesterone binding to the 71 kDa protein in a dosedependent manner. Ligand blot assays performed in the presence of free progesterone, RU486 or estrogen revealed that binding of peroxidase-conjugated progesterone to the 71 kDa protein was inhibited by free progesterone and RU486 in a dose-dependent manner but not by estrogen, which further confirms that progesterone binds to the 71 kDa protein specifically. Furthermore, the progesterone-induced acrosome reaction was inhibited by mAb C-262 in a dose-dependent manner. These results strongly imply that spermatozoa possess a progesterone receptor in a membrane-bound form and can be influenced by progesterone via non-genomic progesterone receptor.

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“…Stimulation of spermatozoa to undergo acrosomal exocytosis results in the activation of phospholipases and the generation of membrane or intracellular messengers (Roldan, 1998;Kopf, 2002). Treatment with progesterone or ZP leads to activation of phosphoinositidase C and phosphatidylcholine (PC)-specific phospholipase C and the ensuing generation of various molecular species of diacylglycerol (DAG) and alkylacyl-glycerols (Roldan et al, 1994a;Murase and Roldan, 1996;O'Toole et al, 1996a;Fukami et al, 2001;Yuan et al, 2001).…”

mentioning

confidence: 94%

“…Under natural conditions, both agonists may interact to bring about exocytosis, with progesterone priming sperm cells to respond to subsequent ZP stimulation (Roldan et al, 1994a). Progesterone role as a physiological agonist, especially as a primer of ZP action, thus deserves further attention (Kopf, 2002).…”

mentioning

confidence: 99%

Progesterone primes zona pellucida‐induced activation of phospholipase A₂ during acrosomal exocytosis in guinea pig spermatozoa

Shi¹,

Chen²,

Yao³

et al. 2005

Journal Cellular Physiology

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We investigated, using guinea-pig spermatozoa as a model, whether phospholipase A2 (PLA2) is involved in progesterone or zona pellucida (ZP)-stimulated acrosomal exocytosis, if progesterone enhances ZP-induced activation of PLA2, and mechanisms underlying PLA2 regulation. Spermatozoa were capacitated and labeled in low Ca2+ medium with [14C]choline chloride or [14C]arachidonic acid, washed, and then exposed to millimolar Ca2+ and progesterone and/or ZP. Each agonist stimulated decrease of phosphatidylcholine (PC) and release of arachidonic acid and lysoPC, indicative of PLA2 activation. Aristolochic acid (a PLA2 inhibitor) abrogated lipid changes and exocytosis, indicating that these lipid changes are essential for exocytosis. Exposure of spermatozoa to submaximal concentrations of both progesterone and ZP resulted in a synergistic increase of arachidonic acid and lysoPC releases, and exocytosis, suggesting that, under natural conditions, both agonists interact to bring about acrosomal exocytosis. Progesterone-induced PLA2 activation appears to be mediated by a GABA(A)-like receptor, because bicuculline (a GABA(A) receptor antagonist) blocked arachidonic acid release and exocytosis. In agreement with this, GABA mimicked progesterone actions. ZP-induced activation of PLA2 seemed to be transduced via G(i) proteins because pertussis toxin blocked arachidonic acid release and acrosomal exocytosis. PLA2 may be regulated by PKC because progesterone- or ZP-induced release of arachidonic acid was blocked by the PKC inhibitors staurosporine or chelerythrine chloride. PLA2 could also be regulated by the cAMP-PKA pathway; inclusion of the PKA inhibitor 14-22 amide or H-89 led to a reduction in arachidonic acid release or exocytosis after progesterone or ZP. Taken together, these results suggest that PLA2 plays an essential role in progesterone or ZP-stimulated exocytosis with progesterone priming ZP action.

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Signal Transduction Mechanisms Regulating Sperm Acrosomal Exocytosis

Cited by 15 publications

References 238 publications

Acrosomal exocytosis of mouse sperm progresses in a consistent direction in response to zona pellucida

Acrosomal exocytosis of mouse sperm progresses in a consistent direction in response to zona pellucida

Identification of a 71 kDa protein as a putative non-genomic membrane progesterone receptor in boar spermatozoa

Progesterone primes zona pellucida‐induced activation of phospholipase A₂ during acrosomal exocytosis in guinea pig spermatozoa

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Signal Transduction Mechanisms Regulating Sperm Acrosomal Exocytosis

Cited by 15 publications

References 238 publications

Acrosomal exocytosis of mouse sperm progresses in a consistent direction in response to zona pellucida

Acrosomal exocytosis of mouse sperm progresses in a consistent direction in response to zona pellucida

Identification of a 71 kDa protein as a putative non-genomic membrane progesterone receptor in boar spermatozoa

Progesterone primes zona pellucida‐induced activation of phospholipase A2 during acrosomal exocytosis in guinea pig spermatozoa

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Progesterone primes zona pellucida‐induced activation of phospholipase A₂ during acrosomal exocytosis in guinea pig spermatozoa