Calcium-triggered acrosomal exocytosis in human spermatozoa requires the coordinated activation of Rab3A and
            <i>N</i>
            -ethylmaleimide-sensitive factor

Michaut, Marcela Alejandra; Tomes, Claudia N.; Blas, Gerardo De; Yunes, Roberto; Mayorga, Luis S.

doi:10.1073/pnas.180206197

Cited by 94 publications

(76 citation statements)

References 40 publications

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“…These data document that no individual Rab3 protein performs an isolated separate function that is required for reproduction or survival. For example, Rab3A or Rab3B KO mice exhibited no apparent decrease in weight or fertility, indicating that contrary to previous hypotheses, these proteins are not required for a fundamental gastrointestinal or reproductive function (Michaut et al, 2000). Most importantly, our data show that the four Rab3 proteins are functionally redundant, despite their differential distributions.…”

Section: Discussioncontrasting

confidence: 77%

A Complete Genetic Analysis of Neuronal Rab3 Function

Schmitz²,

et al. 2004

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Rab3A, Rab3B, Rab3C, and Rab3D are closely related GTP-binding proteins of synaptic vesicles that may function in neurotransmitter release. We have produced knock-out (KO) mice for Rab3B and Rab3C and crossed them with previously generated Rab3A and 3D knock-out mice to generate double, triple, and quadruple Rab3 knock-out mice. We have found that all single and double Rab3 knock-out mice are viable and fertile. Most triple Rab3 knock-out mice perish whenever Rab3A is one of the three deleted proteins, whereas all triple knock-out mice that express Rab3A are viable and fertile. Finally, all quadruple knock-out mice die shortly after birth. Quadruple Rab3 KO mice initially develop normally and are born alive but succumb to respiratory failure. Rab3-deficient mice display no apparent changes in synapse structure or brain composition except for a loss of rabphilin, a Rab3-binding protein. Analysis of cultured hippocampal neurons from quadruple knock-out mice uncovered no significant change in spontaneous or sucrose-evoked release but an ϳ30% decrease in evoked responses. This decrease was caused by a decline in the synaptic and the vesicular release probabilities, suggesting that Rab3 proteins are essential for the normal regulation of Ca 2ϩ -triggered synaptic vesicle exocytosis but not for synaptic vesicle exocytosis as such. Our data show that Rab3 is required for survival in mice and that the four Rab3 proteins are functionally redundant in this role. Furthermore, our data demonstrate that Rab3 is not in itself essential for synaptic membrane traffic but functions to modulate the basic release machinery.

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Section: Discussioncontrasting

confidence: 77%

A Complete Genetic Analysis of Neuronal Rab3 Function

Schmitz²,

et al. 2004

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“…We previously reported that sperm contain a GEF activity that exchanges GDP for GTP on Rab3A when challenged with calcium or 8-pCPT-2′-O-Me-cAMP (35,47). We conducted those earlier experiments in SLO-permeabilized human sperm, but because we performed the Rab27 pull-down experiments reported in this paper with nonpermeabilized sperm, we wished to verify the Rab3A data under the same conditions.…”

Section: Resultsmentioning

confidence: 93%

Rab27 and Rab3 sequentially regulate human sperm dense-core granule exocytosis

Bustos

Lucchesi

Ruete

et al. 2012

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

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Two so-called “secretory Rabs,” Rab3 and Rab27, regulate late steps during dense-core vesicle exocytosis in neuroendocrine cells. Sperm contain a single large dense-core granule that is released by regulated exocytosis (termed the acrosome reaction) during fertilization or on exposure to inducers in vitro. Sperm exocytosis uses the same fusion machinery as neurons and neuroendocrine cells, with an additional requirement for active Rab3. Here we show that Rab27 is also required for the acrosome reaction, as demonstrated by the inability of inducers to elicit exocytosis when streptolysin O-permeabilized human sperm were loaded with inhibitory anti-Rab27 antibodies or the Rab27–GTP binding domain of the effector Slac2-b. The levels of GTP-bound Rab27 increased on initiation of exocytosis, as did the proportion of GTP-bound Rab3A. We have developed a fluorescence microscopy-based method for detecting endogenous Rab3A-GTP and Rab27-GTP in the acrosomal region of human sperm. Challenge with an inducer increased the population of cells exhibiting GTP-bound Rabs in this subcellular domain. Interestingly, introducing recombinant Rab27A loaded with GTP-γ-S into sperm elicited a remarkable increase in the number of cells evincing GTP-bound Rab3A. In the converse condition, recombinant Rab3A did not modify the percentage of Rab27-GTP–containing cells. Furthermore, Rab27A-GTP recruited a Rab3 GDP/GTP exchange factor (GEF) activity. Our findings suggest that Rab27/Rab3A constitutes a Rab-GEF cascade in dense-core vesicle exocytosis.

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“…4B). In the acrosomal proteins in spermatozoa, acrosin (19) and Nethylmaleimide-sensitive factor (NSF), which function in the acrosomal reaction (20,21), were rarely observed in the acrosome and head of sperm from Ht mice (Fig. S5 A-D).…”

Section: Resultsmentioning

confidence: 99%

A heterozygous mutation of GALNTL5 affects male infertility with impairment of sperm motility

Takasaki

Tachibana

Ogasawara

et al. 2014

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

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For normal fertilization in mammals, it is important that functionally mature sperm are motile and have a fully formed acrosome. The glycosyltransferase-like gene, human polypeptide N-acetylgalactosaminyltransferase-like protein 5 (GALNTL5), belongs to the polypeptide N-acetylgalactosamine-transferase (pp-GalNAc-T) gene family because of its conserved glycosyltransferase domains, but it uniquely truncates the C-terminal domain and is expressed exclusively in human testis. However, glycosyltransferase activity of the human GALNTL5 protein has not been identified by in vitro assay thus far. Using mouse Galntl5 ortholog, we have examined whether GALNTL5 is a functional molecule in spermatogenesis. It was observed that mouse GALNTL5 localizes in the cytoplasm of round spermatids in the region around the acrosome of elongating spermatids, and finally in the neck region of spermatozoa. We attempted to establish Galntl5-deficient mutant mice to investigate the role of Galntl5 in spermiogenesis and found that the heterozygous mutation affected male fertility due to immotile sperm, which is diagnosed as asthenozoospermia, an infertility syndrome in humans. Furthermore, the heterozygous mutation of Galntl5 attenuated glycolytic enzymes required for motility, disrupted protein loading into acrosomes, and caused aberrant localization of the ubiquitin-proteasome system. By comparing the protein compositions of sperm from infertile males, we found a deletion mutation of the exon of human GALNTL5 gene in a patient with asthenozoospermia. This strongly suggests that the genetic mutation of human GALNTL5 results in male infertility with the reduction of sperm motility and that GALNTL5 is a functional molecule essential for mammalian sperm formation.

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Calcium-triggered acrosomal exocytosis in human spermatozoa requires the coordinated activation of Rab3A and N -ethylmaleimide-sensitive factor

Cited by 94 publications

References 40 publications

A Complete Genetic Analysis of Neuronal Rab3 Function

A Complete Genetic Analysis of Neuronal Rab3 Function

Rab27 and Rab3 sequentially regulate human sperm dense-core granule exocytosis

A heterozygous mutation of GALNTL5 affects male infertility with impairment of sperm motility

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