Dynamin Regulates Specific Membrane Fusion Events Necessary for Acrosomal Exocytosis in Mouse Spermatozoa

Reid, Andrew T; Lord, Tessa; Stanger, Simone J.; Roman, Shaun D.; McCluskey, Adam; Robinson, Phillip J.; Aitken, R. John; Nixon, Brett

doi:10.1074/jbc.m112.392803

Cited by 45 publications

(52 citation statements)

References 79 publications

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“…Both dynamin-1 and -2 favor diverse types of fusion processes including acrosomal reaction [52], cell to cell fusion [53], [54] and fusion of virus with host cells [55], [56]. In these processes, as in exocytosis [21], dynamin appears to act facilitating the expansion of the fusion pore [52], [56].…”

Section: Discussionmentioning

confidence: 99%

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Dynamin-2 Regulates Fusion Pore Expansion and Quantal Release through a Mechanism that Involves Actin Dynamics in Neuroendocrine Chromaffin Cells

et al. 2013

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Over the past years, dynamin has been implicated in tuning the amount and nature of transmitter released during exocytosis. However, the mechanism involved remains poorly understood. Here, using bovine adrenal chromaffin cells, we investigated whether this mechanism rely on dynamin’s ability to remodel actin cytoskeleton. According to this idea, inhibition of dynamin GTPase activity suppressed the calcium-dependent de novo cortical actin and altered the cortical actin network. Similarly, expression of a small interfering RNA directed against dynamin-2, an isoform highly expressed in chromaffin cells, changed the cortical actin network pattern. Disruption of dynamin-2 function, as well as the pharmacological inhibition of actin polymerization with cytochalasine-D, slowed down fusion pore expansion and increased the quantal size of individual exocytotic events. The effects of cytochalasine-D and dynamin-2 disruption were not additive indicating that dynamin-2 and F-actin regulate the late steps of exocytosis by a common mechanism. Together our data support a model in which dynamin-2 directs actin polymerization at the exocytosis site where both, in concert, adjust the hormone quantal release to efficiently respond to physiological demands.

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Section: Discussionmentioning

confidence: 99%

“…In these processes, as in exocytosis [21], dynamin appears to act facilitating the expansion of the fusion pore [52], [56]. The mechanism is still elusive but likely relies on dynamińs ability to sense curvature and remodel membranes, and probably requires the participation of other molecules.…”

Section: Discussionmentioning

confidence: 99%

Dynamin-2 Regulates Fusion Pore Expansion and Quantal Release through a Mechanism that Involves Actin Dynamics in Neuroendocrine Chromaffin Cells

et al. 2013

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“…Physiological Concentration of P4 Measured in Cumulus Mass Induces AR of Mouse Sperm-In the literature, although numerous concentrations of P4 have been tested to induce AR, from sub-micromolar to tens of micromolars, P4 at 10 -15 M is usually used (20,25,41,42). These concentrations may, however, not represent the physiological concentrations met by the sperm during their journey to oocytes embedded in the cumulus mass.…”

Section: Resultsmentioning

confidence: 99%

Progesterone-induced Acrosome Exocytosis Requires Sequential Involvement of Calcium-independent Phospholipase A2β (iPLA2β) and Group X Secreted Phospholipase A2 (sPLA2)

Nahed

Martinez

Escoffier

et al. 2016

Journal of Biological Chemistry

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Phospholipase A 2 (PLA 2 ) activity has been shown to be involved in the sperm acrosome reaction (AR), but the molecular identity of PLA 2 isoforms has remained elusive. Here, we have tested the role of two intracellular (iPLA 2 ␤ and cytosolic PLA 2 ␣) and one secreted (group X) PLA 2 s in spontaneous and progesterone (P4)-induced AR by using a set of specific inhibitors and knock-out mice. iPLA 2 ␤ is critical for spontaneous AR, whereas both iPLA 2 ␤ and group X secreted PLA 2 are involved in P4-induced AR. Cytosolic PLA 2 ␣ is dispensable in both types of AR. P4-induced AR spreads over 30 min in the mouse, and kinetic analyses suggest the presence of different sperm subpopulations, using distinct PLA 2 pathways to achieve AR. At low P4 concentration (2 M), sperm undergoing early AR (0 -5 min post-P4) rely on iPLA 2 ␤, whereas sperm undergoing late AR (20 -30 min post-P4) rely on group X secreted PLA 2 . Moreover, the role of PLA 2 s in AR depends on P4 concentration, with the PLA 2 s being key actors at low physiological P4 concentrations (<2 M) but not at higher P4 concentrations (ϳ10 M).

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“…Following treatment, spermatozoa were pelleted via centrifugation and resuspended for protein extraction as described previously (Reid et al 2012). Protein extracts were then boiled in the presence of NuPAGE LDS sample buffer (Invitrogen) containing 8% b-mercaptoethanol, subjected to SDS-PAGE using 4-12% BIS-TRIS gels (Invitrogen) and then electrotransferred onto nitrocellulose membranes using conventional western blotting techniques (Towbin et al 1979).…”

Section: Sds-page and Immunoblottingmentioning

confidence: 99%

“…Semen was collected with an open-ended artificial vagina from three adult pony stallions of proven fertility as described previously (Aitken et al 2012). Raw semen was filtered into a sterile collection container and diluted 2:1 in pre-warmed Kenney's extender (Kenney et al 1975), consisting of 133 mM D-glucose, 4.9% (w/v) skimmed milk powder, 2.8 mM Penicillin G sodium salt, and 2.1 mM streptomycin sulphate salt.…”

Section: Collection and Preparation Of Equine Spermatozoamentioning

confidence: 99%

Capacitation in the presence of methyl-β-cyclodextrin results in enhanced zona pellucida-binding ability of stallion spermatozoa

et al. 2014

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While IVF has been widely successful in many domesticated species, the development of a robust IVF system for the horse remains an elusive and highly valued goal. A major impediment to the development of equine IVF is the fact that optimised conditions for the capacitation of equine spermatozoa are yet to be developed. Conversely, it is known that stallion spermatozoa are particularly susceptible to damage arising as a consequence of capacitation-like changes induced prematurely in response to semen handling and transport conditions. To address these limitations, this study sought to develop an effective system to both suppress and promote the in vitro capacitation of stallion spermatozoa. Our data indicated that the latter could be achieved in a bicarbonate-rich medium supplemented with a phosphodiesterase inhibitor, a cyclic AMP analogue, and methyl-b-cyclodextrin, an efficient cholesterolwithdrawing agent. The populations of spermatozoa generated under these conditions displayed a number of hallmarks of capacitation, including elevated levels of tyrosine phosphorylation, a reorganisation of the plasma membrane leading to lipid raft coalescence in the peri-acrosomal region of the sperm head, and a dramatic increase in their ability to interact with heterologous bovine zona pellucida (ZP) and undergo agonist-induced acrosomal exocytosis. Furthermore, this functional transformation was effectively suppressed in media devoid of bicarbonate. Collectively, these results highlight the importance of efficient cholesterol removal in priming stallion spermatozoa for ZP binding in vitro.

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Dynamin Regulates Specific Membrane Fusion Events Necessary for Acrosomal Exocytosis in Mouse Spermatozoa

Cited by 45 publications

References 79 publications

Dynamin-2 Regulates Fusion Pore Expansion and Quantal Release through a Mechanism that Involves Actin Dynamics in Neuroendocrine Chromaffin Cells

Dynamin-2 Regulates Fusion Pore Expansion and Quantal Release through a Mechanism that Involves Actin Dynamics in Neuroendocrine Chromaffin Cells

Progesterone-induced Acrosome Exocytosis Requires Sequential Involvement of Calcium-independent Phospholipase A2β (iPLA2β) and Group X Secreted Phospholipase A2 (sPLA2)

Capacitation in the presence of methyl-β-cyclodextrin results in enhanced zona pellucida-binding ability of stallion spermatozoa

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