Journal ArticleDOI
Rab3A triggers the acrosome reaction in permeabilized human spermatozoa
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TLDR
The results indicate that permeabilized spermatozoa can be used to study the role of macromolecules in the acrosome reaction, Rab3A is present in human spermutozoa, and Rab 3A or another Rab3 isoform is involved in the exocytosis of the Acrosomal granule in human semen.Abstract:
The acrosome reaction is a regulated exocytotic process leading to a massive fusion between the outer acrosomal membrane and the cell membrane. In spite of the great amount of information available related to the acrosome reaction in several species, there is a remarkable paucity about the role of monomeric guanosine triphosphatases (GTPases) of the Rab family—wellestablished participants in exocytosis in other cell types—in the acrosome reaction. Western blot and immunofluorescence analysis indicate that Rab3A is present in human spermatozoa and localizes to the acrosomal region in the sperm head. One difficulty in studying the role of proteins in intact cells is the fact that they are unable to cross the cell membrane. Therefore, we established a working model of streptolysin O-permeabilized human spermatozoa. Permeabilized spermatozoa were able to respond in a regulated way to different stimuli, such as G protein activators and calcium. An acrosomal reaction was also triggered by a Rab3A peptide corresponding to the effector region. More important, recombinant Rab3A protein in the GTP-bound form caused acrosome exocytosis. The same protein loaded with GDP or Rab11 in the GTP-bound form was inactive. Also, recombinant GDI (GDP dissociation inhibitor)—a protein that releases Rab proteins from membrane—inhibited a GTPgS-stimulated acrosome reaction. Our results indicate that 1) permeabilized spermatozoa can be used to study the role of macromolecules in the acrosome reaction, 2) Rab3A is present in human spermatozoa, and 3) Rab3A or another Rab3 isoform is involved in the exocytosis of the acrosomal granule in human spermatozoa.read more
Citations
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Journal ArticleDOI
Secretory Granule Exocytosis
Robert D. Burgoyne,Alan Morgan +1 more
TL;DR: The wide range of cell types in which regulated secretory granule exocytosis occurs is described and the evidence for the expression of the conserved fusion machinery in these cells is assessed.
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A profile of fertilization in mammals
TL;DR: Select aspects of mammalian fertilization are described and some of the latest experimental evidence that bears on this important area of research is addressed.
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Novel signaling pathways involved in sperm acquisition of fertilizing capacity.
Pablo E. Visconti,V.A. Westbrook,Olga Chertihin,Ignacio A. Demarco,Susan B. Sleight,Alan B. Diekman +5 more
TL;DR: Recent progress is discussed in elucidating mechanisms which regulate sperm capacitation, which correlates with cholesterol efflux from the sperm plasma membrane, increased membrane fluidity, modulations in intracellular ion concentrations, hyperpolarization of the sperm Plasma membrane and increased protein tyrosine phosphorylation.
Journal ArticleDOI
Sperm head membrane reorganisation during capacitation.
TL;DR: The latest insights about sperm lipid raft research are covered and how sperm lipid buoy dynamics may relate to sperm-zona binding and the zona-induced acrosome reaction is discussed.
Journal ArticleDOI
Localization Versus Function of Rab3 Proteins: EVIDENCE FOR A COMMON REGULATORY ROLE IN CONTROLLING FUSION *
TL;DR: Coppola et al. as mentioned in this paper examined the properties of all Rab3 proteins in the same assays, with the long-term goal of identifying a common conceptual framework for their functions.
References
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Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4
TL;DR: Using an improved method of gel electrophoresis, many hitherto unknown proteins have been found in bacteriophage T4 and some of these have been identified with specific gene products.
Journal Article
Cleavage of structural proteins during the assemble of the head of bacterio-phage T4
TL;DR: Using an improved method of gel electrophoresis, many hitherto unknown proteins have been found in bacteriophage T4 and some of these have been identified with specific gene products as mentioned in this paper.
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The Physiology of Reproduction
Ernst Knobil,J. D. Neill +1 more
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Wilson Keith P,J.A Black,John A. Thomson,Eunice E. Kim,James P. Griffith,Manuel A. Navia,Murcko Mark A,Stephen P. Chambers,R A Aldape,Scott A. Raybuck +9 more
TL;DR: The high-resolution structure of human ICE in complex with an inhibitor has been determined by X-ray diffraction and confirms the relationship between human ICE and cell-death proteins in other organisms.