title: ROS, thiols and thiol-regulating systems in male gametogenesis.
abstract: BACKGROUND
  During maturation and storage, spermatozoa generate substantial amounts of reactive oxygen species (ROS) and are thus forced to cope with an increasingly oxidative environment that is both needed and detrimental to their biology. Such a janus-faceted intermediate needs to be tightly controlled and this is done by a wide array of redox enzymes. These enzymes not only have to prevent unspecific modifications of essential cellular biomolecules by quenching undesired ROS, but they are also required and often directly involved in critical protein modifications.
  
  
  METHODS
  The present review is conceived to present an update on what is known about critical roles of redox enzymes, whereby special emphasis is put on the family of glutathione peroxidases, which for the time being presents the best characterized tasks during gametogenesis.
  
  
  CONCLUSIONS
  We therefore demonstrate that understanding the function of (seleno)thiol-based oxidases/reductases is not a trivial task and relevant knowledge will be mainly gained by using robust systems, as exemplified by several (conditional) knockout studies. We thus stress the importance of using such models for providing unequivocal evidence in the molecular understanding of redox regulatory mechanisms in sperm maturation.
  
  
  CONCLUSIONS
  ROS are not merely detrimental by-products of metabolism and their proper generation and usage by specific enzymes is essential for vital functions as beautifully exemplified during male gametogenesis. As such, lessons learnt from thiol-based oxidases/reductases in male gametogenesis could be used as a general principle for other organs as it is most likely not only restricted to this developmental phase. This article is part of a Special Issue entitled Redox regulation of differentiation and de-differentiation.
authors.affiliation: Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany. Electronic address: marcus.conrad@helmholtz-muenchen.de.
authors.forename: Marcus
authors.initials: M
authors.lastname: Conrad
authors.affiliation: Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
authors.forename: Irina
authors.initials: I
authors.lastname: Ingold
authors.affiliation: Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
authors.forename: Katalin
authors.initials: K
authors.lastname: Buday
authors.affiliation: Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany; Department of Functional Genomics and Biotechnology, United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Kobayashi
authors.affiliation: Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
authors.forename: Jose Pedro Friedmann
authors.initials: JP
authors.lastname: Angeli
mesh_terms: D000818:Animals; D005979:Glutathione Peroxidase / Q000378:metabolism; D006801:Humans; D008297:Male; D008954:Models, Biological; D010084:Oxidation-Reduction; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013091:Spermatogenesis; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D005979:Glutathione Peroxidase
keywords: Glutathione peroxidase; Oxidative stress; Selenium; Selenoproteins; Spermatogenesis