Multiple Glycolytic Enzymes Are Tightly Bound to the Fibrous Sheath of Mouse Spermatozoa

• Published in: Biology of reproduction Vol. 75; no. 2; pp. 270 - 278
• Main Authors: KRISFALUSI, Michelle, MIKI, Kiyoshi, MAGYAR, Patricia L, O'BRIEN, Deborah A
• Format: Journal Article
• Language: English
• Published: Madison, WI Society for the Study of Reproduction 01.08.2006
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Blotting, Western; Enzymes - analysis; Enzymes - metabolism; Flagella - enzymology; Fructose-Bisphosphate Aldolase - analysis; Fructose-Bisphosphate Aldolase - metabolism; Fundamental and applied biological sciences. Psychology; Glyceraldehyde-3-Phosphate Dehydrogenases - analysis; Glyceraldehyde-3-Phosphate Dehydrogenases - metabolism; Glycolysis; Isoenzymes - analysis; Isoenzymes - metabolism; L-Lactate Dehydrogenase - analysis; L-Lactate Dehydrogenase - metabolism; Male; Mammalian male genital system; Mice; Mice, Inbred Strains; Microscopy, Electron; Molecular Sequence Data; Morphology. Physiology; Spermatozoa - cytology; Spermatozoa - metabolism; Vertebrates: reproduction; Spermatozoa; sperm motility and transport; Motility; fertilization; Enzyme; Biological transport; Rodentia; gamete biology; sperm; Germinal cell; Glycolytic enzyme; Gamete; Vertebrata; Reproduction; Mammalia; Mouse; Animal
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod.105.049684

The fibrous sheath is a cytoskeletal structure located in the principal piece of mammalian sperm flagella. Previous studies showed that glyceraldehyde 3-phosphate dehydrogenase, spermatogenic (GAPDHS), a germ cell-specific glycolytic isozyme that is required for sperm motility, is tightly bound to the fibrous sheath. To determine if other glycolytic enzymes are also bound to this cytoskeletal structure, we isolated highly purified fibrous sheath preparations from mouse epididymal sperm using a sequential extraction procedure. The isolated fibrous sheaths retain typical ultrastructural features and exhibit little contamination by axonemal or outer dense fiber proteins in Western blot analyses. Proteomic analysis using peptide-mass fingerprinting and MS/MS peptide fragment ion matching identified GAPDHS and two additional glycolytic enzyme subunits, the A isoform of aldolase 1 (ALDOA) and lactate dehydrogenase A (LDHA), in isolated fibrous sheaths. The presence of glycolytic enzymes in the fibrous sheath was also examined by Western blotting. In addition to GAPDHS, ALDOA, and LDHA, this method determined that pyruvate kinase is also tightly bound to the fibrous sheath. These data support a role for the fibrous sheath as a scaffold for anchoring multiple glycolytic enzymes along the length of the flagellum to provide a localized source of ATP that is essential for sperm motility. Abstract Multiple glycolytic enzymes are present in highly purified fibrous sheath preparations, suggesting that localization of this central metabolic pathway is essential for regulating sperm motility.