title: Analysis of protein thiol changes occurring during rat sperm epididymal maturation.
abstract: The maturation of spermatozoa throughout the epididymal environment occurs in the complete absence of nuclear protein biosynthesis. As such, these cells rely heavily on posttranslational modifications of existing proteins in order to obtain the potential for fertilization. We have used an OxiCat approach to label both free and oxidized cysteine residues in rat sperm proteins and compared the ratio of reduced:oxidized peptides as these cells undergo epididymal transit. In all, 20 peptides, corresponding to 15 proteins, underwent a change in their redox status. Included in this list were A-kinase anchoring protein 4 and fatty acid-binding protein 9. Both of these proteins undergo intradisulfide bonding, leading to reduced solubility and, in the case of the latter, is likely to cause a loss of protein function. Interestingly, two glycolytic enzymes, hexokinase-1 and lactate dehydrogenase, also display increased cysteine oxidation during epididymal transit, which may be involved in the regulation of the enzyme activities.
authors.affiliation: Discipline of Biological Sciences, University of Newcastle. Callaghan, New South Wales, Australia Mark.Baker@newcastle.edu.au.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Baker
authors.affiliation: Discipline of Biological Sciences, University of Newcastle. Callaghan, New South Wales, Australia.
authors.forename: Anita
authors.initials: A
authors.lastname: Weinberg
authors.affiliation: Discipline of Biological Sciences, University of Newcastle. Callaghan, New South Wales, Australia.
authors.forename: Louise
authors.initials: L
authors.lastname: Hetherington
authors.affiliation: Discipline of Biological Sciences, University of Newcastle. Callaghan, New South Wales, Australia.
authors.forename: Ana Izabel S B
authors.initials: AI
authors.lastname: Villaverde
authors.affiliation: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia.
authors.forename: Tony
authors.initials: T
authors.lastname: Velkov
mesh_terms: D000818:Animals; D004822:Epididymis / Q000502:physiology*; D008297:Male; D008856:Microscopy, Fluorescence; D010084:Oxidation-Reduction; D011499:Protein Processing, Post-Translational; D051381:Rats; D017208:Rats, Wistar; D029589:Seminal Plasma Proteins / Q000032:analysis* / Q000378:metabolism*; D013079:Sperm Maturation; D013094:Spermatozoa / Q000737:chemistry / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000032:analysis* / Q000378:metabolism
chemical_list: D029589:Seminal Plasma Proteins; D013438:Sulfhydryl Compounds
keywords: OxiCat; cysteine oxidation; epididymis; proteomics; sperm maturation