Immunocytochemical and biochemical characterization of guanine nucleotide-binding regulatory proteins in mammalian spermatozoa

Glassner, M.J.; Jones, J.C.; Kligman, Isaac; Woolkalís, Marílyn J.; Gerton, George L.; Kopf, Gregory S.

doi:10.1016/0012-1606(91)90245-x

Cited by 78 publications

(38 citation statements)

References 36 publications

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“…Unexpectedly, the yeast V-ATPase containing the E1 isoform exhibited a temperature-sensitive defect in coupling between proton transport and ATP hydrolysis. The temperature sensitivity may be consistent with the lower optimal temperature (ϳ33°C) for the culture of spermatid cells (32,33). The present results also indicate that E subunit is essential for energy coupling, and V-ATPase became temperature-sensitive because the yeast Vma4p was replaced by mouse E1.…”

Section: Figsupporting

confidence: 84%

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A Proton Pump ATPase with Testis-specific E1-Subunit Isoform Required for Acrosome Acidification

Sun‐Wada¹,

Imai-Senga²,

Yamamoto³

et al. 2002

Journal of Biological Chemistry

107

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The vacuolar-type H؉ -ATPases (V-ATPases) are a family of multimeric proton pumps involved in a wide variety of physiological processes. We have identified two novel mouse genes, Atp6e1 and Atp6e2, encoding testisspecific (E1) and ubiquitous (E2) V-ATPase subunit E isoforms, respectively. The E1 transcript appears about 3 weeks after birth, corresponding to the start of meiosis, and is expressed specifically in round spermatids in seminiferous tubules. Immunohistochemistry with isoform-specific antibodies revealed that the V-ATPase with E1 and a2 isoforms is located specifically in developing acrosomes of spermatids and acrosomes in mature sperm. In contrast, the E2 isoform was expressed in all tissues examined and present in the perinuclear compartments of spermatocytes. The E1 isoform exhibits 70% identity with the E2, and both isoforms functionally complemented a null mutation of the yeast counterpart VMA4, indicating that they are bona fide V-ATPase subunits. The chimeric enzymes showed slightly lower K m ATP than yeast V-ATPase. Consistent with the temperature-sensitive growth of ⌬vma4-expressing E1 isoform, vacuolar membrane vesicles exhibited temperature-sensitive coupling between ATP hydrolysis and proton transport. These results suggest that E1 isoform is essential for energy coupling involved in acidification of acrosome. Vacuolar Hϩ -ATPase (V-ATPase), 1 an ATP-dependent proton pump, is one of the ubiquitous eukaryotic enzymes. It is present in endomembrane organelles such as vacuoles, lysosomes, endosomes, Golgi apparatus, chromaffin granules, and coated vesicles (1-3) and is also found in the plasma membranes of specialized cells including osteoclasts and renal epithelial cells (4, 5). V-ATPase is required for diverse cellular processes including receptor-mediated endocytosis, renal acidification, bone resorption, neurotransmitter accumulation, and activation of acid hydrolases (2).V-ATPase (V 1 V 0 ) has a similar structure and mechanism to F-type ATPase (ATP synthase, F 1 F 0 ), and their ATP-dependent conformational changes are transmitted between the peripheral complex (V 1 or F 1 ) and the proton pore (V 0 or F 0 ) through a number of subunits forming a stalk (1-3). Deletion of mammalian V o subunit c, encoded by a single gene (6, 7), has been shown to cause an embryonic lethal phenotype (8, 9). One of the most important questions is how a ubiquitous V-ATPase can function in a wide variety of physiological processes.The diverse functions of V-ATPase may be established by utilizing a specific subunit isoform(s), its basic functional structure being maintained. Multiple subunit isoforms have been found for the largest subunit, a, of the V 0 sector in nematode (10), chicken (11), mouse (12-15), and man (16). a4 is specifically expressed in renal intercalated cells (14,17), and its mutations cause renal acidosis (17), whereas a defect of a3, a component of the osteoclast plasma membrane enzyme (12), results in osteopetrosis (18). The only reported isoforms of the mammalian V 1 sector is the B subun...

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Section: Figsupporting

confidence: 84%

“…Immunohistochemistry, Fluorescence Microscopy, and LysoTracker Staining-Adult male ICR mice were used as the source for the isolation of testes, spermatogenic cells, and sperm (32,33). Immunohistochemistry of testis cryo-sections (6 m) was performed as previously described (14).…”

Section: Isolation Of E1 and E2 Cdnas-poly (A)mentioning

confidence: 99%

A Proton Pump ATPase with Testis-specific E1-Subunit Isoform Required for Acrosome Acidification

Sun‐Wada¹,

Imai-Senga²,

Yamamoto³

et al. 2002

Journal of Biological Chemistry

107

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“…The simultaneous application of PGE 1 and progesterone had an additive effect on the induction of AR in capacitated spermatozoa. Whereas capacitation was not required for progesterone (34) and PGE 1 Mammalian sperm express PTX-sensitive G proteins of the G i͞o -family as well as G z (10). In the present study, we analyzed the expression of PTX-insensitive G proteins in membranes from human sperm and showed that G␣ q and G␣ 11 can be detected in sperm membranes whereas no appreciable amounts of G proteins of the G 12͞13 family nor G s were observed.…”

Section: Discussionmentioning

confidence: 64%

“…One of the essential features of the AR is an influx of Ca 2ϩ from the extracellular space required to promote the fusion between the outer acrosomal membrane and the overlying sperm plasma membrane (1). The lack of knowledge on signaling steps leading to Ca 2ϩ influx and AR contrasts with the detailed information about the expression and subcellular localization of classical signal transduction components like G protein-coupled receptors (8), receptor kinases (9), G proteins (10,11), and effectors such as enzymes (11) and ion channels (12). Thus, the delineation of signaling cascades in sperm is a crucial first step to understand the physiology of fertilization at the molecular level.…”

mentioning

confidence: 99%

A new prostaglandin E receptor mediates calcium influx and acrosome reaction in human spermatozoa

Schaefer

Hofmann

Schultz

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

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Zona pellucida protein 3, a protein of the egg's extracellular matrix, and progesterone secreted by granulosa cells surrounding the oocyte are regarded as physiological stimuli of sperm acrosome reaction. Signal transduction steps initiated by both stimuli result in influx of Ca 2؉ from the extracellular space. Herein, we propose a role for prostaglandin (PG) E as a physiological inducer of Ca 2؉ In vivo, ejaculated and epididymal mammalian spermatozoa are not able to fertilize an egg immediately but have to undergo a process of maturation in the female reproductive tract. This time-dependent acquisition of fertilizing capacity called ''capacitation'' is correlated with changes in sperm motility, metabolism, plasma membrane fluidity, and intracellular ion concentrations (1). In capacitated spermatozoa, local stimuli acting in vicinity of the oocyte induce the acrosome reaction (AR), an exocytotic event leading to release of hydrolytic enzymes and substantial reorganization of the sperm plasma membrane (1). To date, two physiological inducers of the AR are known: Subsequent to species-specific binding of sperm to the zona pellucida (ZP), the oocyte's extracellular matrix (2-4), one of the three major proteins forming the mouse ZP, ZP3, elicits the AR (5). Progesterone secreted by ovarian follicular cells surrounding the ovulated egg also initiates the AR (6), and a priming role of the steroid for the induction of the AR by the ZP has been suggested (7).Signal transduction steps in sperm resulting in AR are understood poorly. One of the essential features of the AR is an influx of Ca 2ϩ from the extracellular space required to promote the fusion between the outer acrosomal membrane and the overlying sperm plasma membrane (1). The lack of knowledge on signaling steps leading to Ca 2ϩ influx and AR contrasts with the detailed information about the expression and subcellular localization of classical signal transduction components like G protein-coupled receptors (8), receptor kinases (9), G proteins (10, 11), and effectors such as enzymes (11) and ion channels (12). Thus, the delineation of signaling cascades in sperm is a crucial first step to understand the physiology of fertilization at the molecular level.In the present study, we identified a new role for E prostaglandins as physiological inducers of the AR in humans and provide evidence for the expression of a G protein-coupled E prostanoid (EP) receptor in human sperm. MATERIALS AND METHODSSperm Sample Preparation. Human semen samples were obtained from couples undergoing in vitro fertilization because of female infertility. Sperm samples with normal parameters of sperm count, motility, and morphology were pooled and included in this study. Motile sperm fractions were isolated by a swim-up procedure in hypertonic Biggers Whitten and Whittingham (BWW) medium (for composition, see refs. 13 and 14) supplemented with 10% fetal calf serum (BWW-FCS). Capacitation was promoted by incubating sperm suspensions (0.5-2 ϫ 10 7 per ml) for 6-8 h at 37°C in a humi...

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“…Pertussis toxin (PTX), a specific inhibitor of the G i class of heterotrimeric G proteins, inhibits the ZPinduced AR and its associated ion fluxes in mouse, bovine, and human sperm [108][109][110]. Based on this conformity, several G proteins have been identified in mammalian sperm, such as G i and G z [111], and ZP activates G i1 and G i2 in mouse sperm [112]. Ca 2+ channels can be regulated by G proteins [113], because it is believed that the PTXsensitive step is the ZP-induced pH i increase necessary for the AR [114].…”

Section: Capacitation and Acrosome Reactionmentioning

confidence: 99%

Defining the roles of Ca2+ — permeable channels in sperm

Islam

2006

Open Life Sciences

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Ion channels exert a vital role in the dialogue between male and female gametes and thus in the generation of new individuals in many species. Intracellular Ca 2+ is possibly the key messenger between gametes. Different Ca 2+ -permeable channels have been detected in the plasma membrane and in the organelle-like acrosome membrane of sperm, which play vital roles in determining sperm fertilizing ability. Recent reports from several laboratories have adequately documented that the Ca 2+ -permeable channels of a sperm control a variety of functions ranging from motility to the acrosome reaction. In this article, we have reviewed the data from our and other laboratories, and have documented the mechanisms of different Ca 2+ -permeable channels involved in the fertilization event.

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Immunocytochemical and biochemical characterization of guanine nucleotide-binding regulatory proteins in mammalian spermatozoa

Cited by 78 publications

References 36 publications

A Proton Pump ATPase with Testis-specific E1-Subunit Isoform Required for Acrosome Acidification

A Proton Pump ATPase with Testis-specific E1-Subunit Isoform Required for Acrosome Acidification

A new prostaglandin E receptor mediates calcium influx and acrosome reaction in human spermatozoa

Defining the roles of Ca2+ — permeable channels in sperm

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