title: Thiol changes during epididymal maturation: a link to flagellar angulation in mouse spermatozoa?
abstract: Caput epididymal wild-type spermatozoa and cauda epididymal spermatozoa from mice null for the adenylyl cyclase Adcy10 gene are immotile unless stimulated by a membrane-permeant cyclic AMP analogue. Both types of spermatozoa exhibit flagellar angulation where the head folds back under these conditions. As sperm proteins undergo oxidation of sulfhydryl groups and the flagellum becomes more stable to external forces during epididymal transit, we hypothesized that ADCY10 is involved in a mechanism regulating flagellar stabilization. Although no differences were observed in global sulfhydryl status between caput and cauda epididymal spermatozoa from wild-type or Adcy10-null mice, two-dimensional fluorescence difference gel electrophoresis was performed to identify specific mouse sperm proteins containing sulfhydryl groups that became oxidized during epididymal maturation. A-kinase anchor protein 4, fatty acid-binding protein 9 (FABP9), glutathione S-transferase mu 5 and voltage-dependent anion channel 2 exhibited changes in thiol status between caput and cauda epididymal spermatozoa. The level and thiol status of each of these proteins were quantified in wild-type and Adcy10-null cauda epididymal spermatozoa. No differences in the abundance of any protein were observed; however, FABP9 in Adcy10-null cauda epididymal spermatozoa contained fewer disulfide bonds than wild-type sperm cells. In caput epididymal spermatozoa, FABP9 was detected in the cytoplasmic droplet, principal piece, midpiece, and non-acrosomal area of the head. However, in cauda epididymal spermatozoa, this protein localized to the perforatorium, post-acrosomal region and principal piece. Together, these results suggest that thiol changes during epididymal maturation have a role in the stabilization of the sperm flagellum.
authors.affiliation: Center for Research on Reproduction and Women's Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Molecular Biosciences, Kyoto Sangyo University, Kyoto, Japan.
authors.forename: T W
authors.initials: TW
authors.lastname: Ijiri
authors.forename: M L
authors.initials: ML
authors.lastname: Vadnais
authors.forename: A P
authors.initials: AP
authors.lastname: Huang
authors.forename: A M
authors.initials: AM
authors.lastname: Lin
authors.forename: L R
authors.initials: LR
authors.lastname: Levin
authors.forename: J
authors.initials: J
authors.lastname: Buck
authors.forename: G L
authors.initials: GL
authors.lastname: Gerton
mesh_terms: D054758:A Kinase Anchor Proteins / Q000737:chemistry; D000262:Adenylyl Cyclases / Q000235:genetics*; D000818:Animals; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry; D004822:Epididymis / Q000737:chemistry* / Q000196:embryology / Q000254:growth & development; D050556:Fatty Acid-Binding Proteins / Q000737:chemistry; D005407:Flagella / Q000502:physiology*; D005982:Glutathione Transferase / Q000737:chemistry; D007248:Infertility, Male / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010084:Oxidation-Reduction; D013094:Spermatozoa / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D050996:Voltage-Dependent Anion Channel 2 / Q000737:chemistry
chemical_list: D054758:A Kinase Anchor Proteins; C485479:Akap4 protein, mouse; D004220:Disulfides; C484252:Fabp9 protein, mouse; D050556:Fatty Acid-Binding Proteins; D013438:Sulfhydryl Compounds; C494766:Vdac2 protein, mouse; D050996:Voltage-Dependent Anion Channel 2; D000242:Cyclic AMP; D005982:Glutathione Transferase; C540306:glutathione S-transferase M5, mouse; D000262:Adenylyl Cyclases
keywords: epididymis; sperm function; spermatozoa