Regional differentiation of the sea urchin sperm plasma membrane.

Toowicharanont, P.; Shapiro, Bennett M.

doi:10.1016/s0021-9258(18)68726-5

Cited by 23 publications

(7 citation statements)

References 29 publications

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“…Localization of AC to the flagellum is in agreement with recent data showing that membranes of the flagellum compared to membranes from the sperm head are enriched 28fold in AC activity (24). Flagellar membranes, relative to head membranes are also enriched 14-fold in cAMP phosphodiesterase and 6.5-fold in sites for the calcium channel antagonist D-600 (24). Values for enrichment of guanylate cyclase in flagella versus heads of sea urchin sperm vary from two- (24) to eight- (19) fold.…”

Section: Discussionsupporting

confidence: 90%

“…This location is the part of the flagellum closest to the site of ATP production in the single large mitochondrion midpiece, which is at the posterior part of the sperm head. Localization of AC to the flagellum is in agreement with recent data showing that membranes of the flagellum compared to membranes from the sperm head are enriched 28fold in AC activity (24). Flagellar membranes, relative to head membranes are also enriched 14-fold in cAMP phosphodiesterase and 6.5-fold in sites for the calcium channel antagonist D-600 (24).…”

Section: Discussionsupporting

confidence: 90%

“…Flagellar membranes, relative to head membranes are also enriched 14-fold in cAMP phosphodiesterase and 6.5-fold in sites for the calcium channel antagonist D-600 (24). Values for enrichment of guanylate cyclase in flagella versus heads of sea urchin sperm vary from two- (24) to eight- (19) fold. Membrane preparations derived from sea urchin sperm flagella are enriched 8-15fold in AC activity (13).…”

Section: Discussionmentioning

confidence: 98%

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Identification of sea urchin sperm adenylate cyclase.

Bookbinder

Moy

Vacquier

1990

The Journal of Cell Biology

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Abstract. Calmodulin (CAM) affinity chromatography of a detergent extract of sea urchin sperm yielded ,°20 major proteins. One of these proteins, of Mr 190,000, was purified and used to immunize rabbits. After absorption with living sperm, the serum reacted monospecifically on one-and two-dimensional Western immunoblots with the Mr 190,000 protein. The anti-190-kD serum inhibited 94% of the adenylate cyclase (AC) activity of the CaM eluate. An immunoaffinity column removed 95 % of the AC activity, and the purified (but inactive) Mr 190,000 protein was eluted from the column. The antiserum also inhibited 28 % of the activity of bovine brain CaM-sensitive AC and 90% of the activity of horse sperm CaM-sensitive AC. These data support the hypothesis that the Mr 190,000 protein is sea urchin sperm AC. Although this AC bound to CaM, it was not possible to demonstrate directly a Ca 2÷ or CaM sensitivity. However, two CaM antagonists, calmidazolium and chlorpromazine, both inhibited AC activity, and the inhibition was released by added CaM, suggesting the possibility of regulation of this AC by CaM. Indirect immunofluorescence showed the Mr 190,000 protein to be highly concentrated on only the proximal half of the sea urchin sperm flagellum. This asymmetric localization of AC may be important to its function in flagellar motility. This is the first report of the identification of an AC from animal spermatozoa.IMAL spermatozoa undergo profound physiological changes between the time of their release from the male reproductive tract and their fusion with eggs. Some of these changes, or "activations" are the initiation of motility, capacitation, and the acrosome reaction. A large literature exists on the regulation of the initiation of sperm flagellar motility by Ca 2÷, cAMP, and cAMP-dependent protein kinase (A-kinase; for reviews, see references 1,3,8, 11,21,22). In summary, these data support the hypothesis that increases in cellular Ca 2÷ activate sperm adenylate cyclase, resulting in increased concentrations of cAMP. This in turn activates A-kinase, which phosphorylates axonemal proteins. These phosphorylation events are necessary for the initiation and maintenance of flagellar motility. Sea urchin sperm are a model cell for studying the mechanism of flagellar motility. It is important to the ultimate elucidation of the underlying mechanism to identify, localize, and characterize the enzymes and their protein substrates that function in the process.Previous work (reviewed in reference 3) has shown that sea urchin spermatozoa contain considerable adenylate cyclase (AC) ~ activity. This activity requires Mn-ATP and exhibits a 50-fold activation when living sperm are treated with solu-L. H. Bookbinders present address is Department of Pharmacology, S J-30,

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Section: Discussionsupporting

confidence: 90%

Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 98%

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Identification of sea urchin sperm adenylate cyclase.

Bookbinder

Moy

Vacquier

1990

The Journal of Cell Biology

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“…It has been reported that there are differences in the composition of the flagellar and head sperm plasma membranes (Garcla-Soto et al, 1988;Toowicharanont and Shapiro, 1988). However, both membrane fractions share components like the putative 210 kD egg jelly receptor (Trimmer et al, 1985) and high affinity sites for dihydropyridines (Garcia-Soto et al, 1988) and verapamil (Toowicharanont and Shapiro, 1988). Also, they both respond in a similar fashion when exposed to egg jelly, increasing their uptake of 4SCa2+ and 22Na+ (Darszon et al, 1984;Garcia-Soto et al, 1988).…”

Section: Discussionmentioning

confidence: 95%

“…The acrosome reaction occurs in the sperm head, thus it could be argued that the channels present in the flageUar plasma membrane are not involved in this reaction. It has been reported that there are differences in the composition of the flagellar and head sperm plasma membranes (Garcla-Soto et al, 1988;Toowicharanont and Shapiro, 1988). However, both membrane fractions share components like the putative 210 kD egg jelly receptor (Trimmer et al, 1985) and high affinity sites for dihydropyridines (Garcia-Soto et al, 1988) and verapamil (Toowicharanont and Shapiro, 1988).…”

Section: Discussionmentioning

confidence: 98%

Ca2+ channels from the sea urchin sperm plasma membrane.

Liévano

Vega-SaenzdeMiera

Darszon

1990

The Journal of General Physiology

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Ca ~+ influx across the sea urchin sperm plasma membrane is a necessary step during the egg jelly-induced acrosome reaction. There is pharmacological evidence for the involvement of Ca 2+ channels in this influx, but their presence has not been directly demonstrated because of the small size of this cell. Sea urchin sperm Ca 2+ channels are being studied by fusing isolated plasma membranes into planar lipid brayers. With this strategy, a Ca P+ channel has been detected with the following characteristics: (a) the channel exhibits a high mainstate conductance (3'MS) of 172 pS in 50 mM CaCIp solutions with voltage-dependent decaying to smaller conductance states at negative Era; (b) the channel is blocked by millimolar concentrations of Cd 2+, Co P+, and La 3+, which also inhibit the egg jelly-induced acrosome reaction; (c) the "yMS conductance sequence for the tested divalent cations is the following: Ba P+ > Sr P+ > Ca2+; and (d) the channel discriminates poorly for divalent over monovalent cations (Pc~/PN~ = 5.9). The sperm Ca P+ channel 3'MS rectifies in symmetrical 10 mM CaC12, having a maximal slope conductance value of 94 pS at + 100 mV applied to the c/s side of the bilayer. Under these conditions, a different single-channel activity of lesser conductance became apparent above the "}'MS current at positive membrane potentials. Also in 10 mM Ca P+ solutions, Mg ~+ permeates through the main channel when added to the c/s side with a Pc~/PMg = 2.9, while it blocks when added to the trans side. In 50 mM Ca P+ solutions, the ")'MS open probability has values of 1.0 at voltages more positive than -40 mV and decreases at more negatives potentials, following a Boltzmann function with an E0.s = -72 mV and an apparent gating charge value of 3.9. These results describe a novel CaP+-selective channel, and suggest that the main channel works as a single multipore assembly.

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Signal transduction mechanisms regulating ion fluxes in the sea urchin sperm

Beltrán

Galindo

Rodríguez‐Miranda

et al. 2007

Signal Transduction

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Ion permeability changes involving ion channels and transporters are essential for fertilization, since they are key elements in sperm‐egg signaling and environmental sensing. Changes modulated by external factors and components from the outer layer of the homologous egg, like the sperm‐activating peptides and the fucose‐sulfate glycoconjugate, trigger complex signaling systems in the sperm that modulate how sperm swim, find the egg and fertilize it. These signaling systems depend on plasma membrane ion permeability and involve an alteration of second messenger levels, changes of membrane potential and intracellular Ca2+, Na+ and pH, along with changes in sperm morphology in the case of the acrosome reaction (AR). New procedures to elucidate the signaling pathways implicated in sperm ion transport have expanded the opportunities to dissect sperm‐egg signaling revealing how sperm ion channels participate in activation, motility, chemotaxis, and the AR. The sperm signaling pathways involve a large variety of ion channels and transporters, which are discretely localized and finely orchestrated to play specific roles that define the elaborate performance of sperm and allow a successful fertilization. In this review we will focus on the signaling molecules involved in the final aim of the sperm, to reach and fertilize the egg.

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Regional differentiation of the sea urchin sperm plasma membrane.

Cited by 23 publications

References 29 publications

Identification of sea urchin sperm adenylate cyclase.

Identification of sea urchin sperm adenylate cyclase.

Ca2+ channels from the sea urchin sperm plasma membrane.

Signal transduction mechanisms regulating ion fluxes in the sea urchin sperm

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