scholarly journals Complexin I is required for mammalian sperm acrosomal exocytosis

2007 ◽  
Vol 309 (2) ◽  
pp. 236-244 ◽  
Author(s):  
Longmei Zhao ◽  
Heather R. Burkin ◽  
Xudong Shi ◽  
Lingjun Li ◽  
Kerstin Reim ◽  
...  
Keyword(s):  
Mammalian Sperm ◽  
Acrosomal Exocytosis

Ionic control of sperm function

1995 ◽  
Vol 7 (4) ◽  
pp. 905 ◽  
Author(s):  
LR Fraser
Keyword(s):  
Ionic Composition ◽  
Ion Fluxes ◽  
Sperm Function ◽  
Considerable Evidence ◽  
Functional Potential ◽  
Mammalian Sperm ◽  
Acrosomal Exocytosis ◽  
Extracellular Environment

Successful sperm function leads to fertilization. It is dependent on the extracellular environment, especially the array and concentration of various ions. Considerable evidence indicates that this is because of consequent effects on the intracellular ionic composition. Although both cations and anions undoubtedly play a role in a modulating sperm function, most of the evidence currently available concerns cations. Therefore, this review will concentrate on cations, focussing on Ca2+, Na+, K+ and H+. Their requirements for successful capacitation (mammalian sperm) and acrosomal exocytosis (both invertebrate and mammalian sperm) will be considered. In particular, the mechanisms which may control ion fluxes, leading to changes in the intracellular ionic composition and subsequently to changes in sperm functional potential, will be addressed.

scholarly journals Discrete Dynamic Model of the Mammalian Sperm Acrosome Reaction: The Influence of Acrosomal pH and Physiological Heterogeneity

2021 ◽  
Vol 12 ◽  
Author(s):  
Andrés Aldana ◽  
Jorge Carneiro ◽  
Gustavo Martínez-Mekler ◽  
Alberto Darszon
Keyword(s):  
Acrosome Reaction ◽  
Human Sperm ◽  
Extracellular Medium ◽  
Mammalian Sperm ◽  
Discrete Dynamic Model ◽  
Acrosomal Exocytosis ◽  
Mammalian Fertilization ◽  
Main Components ◽  
Discrete Mathematical Model ◽  
Physiological Heterogeneity

The acrosome reaction (AR) is an exocytotic process essential for mammalian fertilization. It involves diverse physiological changes (biochemical, biophysical, and morphological) that culminate in the release of the acrosomal content to the extracellular medium as well as a reorganization of the plasma membrane (PM) that allows sperm to interact and fuse with the egg. In spite of many efforts, there are still important pending questions regarding the molecular mechanism regulating the AR. Particularly, the contribution of acrosomal alkalinization to AR triggering physiological conditions is not well understood. Also, the dependence of the proportion of sperm capable of undergoing AR on the physiological heterogeneity within a sperm population has not been studied. Here, we present a discrete mathematical model for the human sperm AR based on the physiological interactions among some of the main components of this complex exocytotic process. We show that this model can qualitatively reproduce diverse experimental results, and that it can be used to analyze how acrosomal pH (pHa) and cell heterogeneity regulate AR. Our results confirm that a pHa increase can on its own trigger AR in a subpopulation of sperm, and furthermore, it indicates that this is a necessary step to trigger acrosomal exocytosis through progesterone, a known natural inducer of AR. Most importantly, we show that the proportion of sperm undergoing AR is directly related to the detailed structure of the population physiological heterogeneity.

scholarly journals Heads or tails? Structural events and molecular mechanisms that promote mammalian sperm acrosomal exocytosis and motility

2011 ◽  
Vol 79 (1) ◽  
pp. 4-18 ◽  
Author(s):  
Mariano G. Buffone ◽  
Takashi W. Ijiri ◽  
Wenlei Cao ◽  
Tanya Merdiushev ◽  
Haig K. Aghajanian ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Mammalian Sperm ◽  
Acrosomal Exocytosis

scholarly journals Parkinson Disease Protein 7 (PARK7) Is Related to the Ability of Mammalian Sperm to Undergo In Vitro Capacitation

2021 ◽  
Vol 22 (19) ◽  
pp. 10804
Author(s):  
Sandra Recuero ◽  
Ariadna Delgado-Bermúdez ◽  
Yentel Mateo-Otero ◽  
Estela Garcia-Bonavila ◽  
Marc Llavanera ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Parkinson Disease ◽  
Intracellular Calcium ◽  
Sperm Motility ◽  
Antioxidant Properties ◽  
Lipid Disorder ◽  
Mammalian Sperm ◽  
Acrosomal Exocytosis ◽  
Disease Protein

Parkinson disease protein 7 (PARK7) is a multifunctional protein known to be involved in the regulation of sperm motility, mitochondrial function, and oxidative stress response in mammalian sperm. While ROS generation is needed to activate the downstream signaling pathways required for sperm to undergo capacitation, oxidative stress has detrimental effects for sperm cells and a precise balance between ROS levels and antioxidant activity is needed. Considering the putative antioxidant role of PARK7, the present work sought to determine whether this protein is related to the sperm ability to withstand in vitro capacitation. To this end, and using the pig as a model, semen samples were incubated in capacitation medium for 300 min; the acrosomal exocytosis was triggered by the addition of progesterone after 240 min of incubation. At each relevant time point (0, 120, 240, 250, and 300 min), sperm motility, acrosome and plasma membrane integrity, membrane lipid disorder, mitochondrial membrane potential, intracellular calcium and ROS were evaluated. In addition, localization and protein levels of PARK7 were also assessed through immunofluorescence and immunoblotting. Based on the relative content of PARK7, two groups of samples were set. As early as 120 min of incubation, sperm samples with larger PARK7 content showed higher percentages of viable and acrosome-intact sperm, lipid disorder and superoxide levels, and lower intracellular calcium levels when compared to sperm samples with lower PARK7. These data suggest that PARK7 could play a role in preventing sperm from undergoing premature capacitation, maintaining sperm viability and providing a better ability to keep ROS homeostasis, which is needed to elicit sperm capacitation. Further studies are required to elucidate the antioxidant properties of PARK7 during in vitro capacitation and acrosomal exocytosis of mammalian sperm, and the relationship between PARK7 and sperm motility.

scholarly journals Membrane Remodeling and Matrix Dispersal Intermediates During Mammalian Acrosomal Exocytosis

2021 ◽  
Vol 9 ◽  
Author(s):  
Miguel Ricardo Leung ◽  
Ravi Teja Ravi ◽  
Bart M. Gadella ◽  
Tzviya Zeev-Ben-Mordehai
Keyword(s):  
Plasma Membrane ◽  
Reproductive Tract ◽  
Morphological Changes ◽  
Female Reproductive Tract ◽  
Cell Integrity ◽  
Membrane Fission ◽  
Mammalian Sperm ◽  
Acrosomal Exocytosis ◽  
Plausible Mechanism ◽  
Structural Mechanisms

To become fertilization-competent, mammalian sperm must undergo a complex series of biochemical and morphological changes in the female reproductive tract. These changes, collectively called capacitation, culminate in the exocytosis of the acrosome, a large vesicle overlying the nucleus. Acrosomal exocytosis is not an all-or-nothing event but rather a regulated process in which vesicle cargo disperses gradually. However, the structural mechanisms underlying this controlled release remain undefined. In addition, unlike other exocytotic events, fusing membranes are shed as vesicles; the cell thus loses the entire anterior two-thirds of its plasma membrane and yet remains intact, while the remaining nonvesiculated plasma membrane becomes fusogenic. Precisely how cell integrity is maintained throughout this drastic vesiculation process is unclear, as is how it ultimately leads to the acquisition of fusion competence. Here, we use cryoelectron tomography to visualize these processes in unfixed, unstained, fully hydrated sperm. We show that paracrystalline structures within the acrosome disassemble during capacitation and acrosomal exocytosis, representing a plausible mechanism for gradual dispersal of the acrosomal matrix. We find that the architecture of the sperm head supports an atypical membrane fission–fusion pathway that maintains cell integrity. Finally, we detail how the acrosome reaction transforms both the micron-scale topography and the nanoscale protein landscape of the sperm surface, thus priming the sperm for fertilization.

scholarly journals Discrete dynamic model of the mammalian sperm acrosome reaction: the influence of acrosomal pH and biochemical heterogeneity

2021 ◽  
Author(s):  
Andrés Aldana ◽  
Jorge Carneiro ◽  
Gustavo Martínez-Mekler ◽  
Alberto Darszon
Keyword(s):  
Acrosome Reaction ◽  
Human Sperm ◽  
Extracellular Medium ◽  
Mammalian Sperm ◽  
Discrete Dynamic Model ◽  
Acrosomal Exocytosis ◽  
Mammalian Fertilization ◽  
Main Components ◽  
Discrete Mathematical Model ◽  
Sperm Acrosome Reaction

AbstractThe acrosome reaction (AR) is an exocytotic process essential for mammalian fertilization. It involves diverse biochemical and physiological changes that culminate in the release of the acrosomal content to the extracellular medium as well as a reorganization of the plasma membrane (PM) that allows sperm to interact and fuse with the egg. In spite of many efforts, there are still important pending questions regarding the molecular mechanism regulating the AR. Particularly, the contribution of acrosomal alkalinization to AR triggering in physiological conditions is not well understood. Also, the dependence of the proportion of sperm capable of undergoing AR on the biochemical heterogeneity within a sperm population has not been studied. Here we present a discrete mathematical model for the human sperm AR, based on the biophysical and biochemical interactions among some of the main components of this complex exocytotic process. We show that this model can qualitatively reproduce diverse experimental results, and that it can be used to analyze how acrosomal pH (pHa) and cell heterogeneity regulate AR. Our results confirm that pHa increase can on its own trigger AR in a subpopulation of sperm, and furthermore, it indicates that this is a necessary step to trigger acrosomal exocytosis through progesterone, a known physiological inducer of AR. Most importantly, we show that the proportion of sperm undergoing AR is directly related to the detailed structure of the population biochemical heterogeneity.

scholarly journals Molecular and Cellular Aspects of Mammalian Sperm Acrosomal Exocytosis

2017 ◽  
pp. 409-426
Author(s):  
Florenza A. La Spina ◽  
Cintia Stival ◽  
Dario Krapf ◽  
Mariano G. Buffone
Keyword(s):  
Mammalian Sperm ◽  
Acrosomal Exocytosis
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