Male mice express spermatogenic cell‐specific triosephosphate isomerase isozymes

Abstract

Triosephosphate isomerase 1 (TPI1) is a member of the glycolytic pathway, which is a critical source of energy for motility in mouse sperm. By immunoblotting, we detected two male, germ line-specific TPI1 bands (Mr 33,400 and 30,800) as well as the somatic-type band (Mr 27,700). Although all three bands were observed in spermatogenic cells, somatic-type TPI1 disappeared from sperm during epididymal maturation. In vitro dephosphorylation analysis suggested that the two male, germ line-specific TPI1 bands were not the result of phosphorylation of the 27,700 Mr TPI1 band. The Mr 33,400; 30,800; and 27,700 TPI1 bands corresponded to the respective sizes of the proteins predicted to use the first, second, and third possible initiation codons of the Tpi1 cDNA. We performed immunofluorescence on epididymal sperm and determined that TPI1 specifically localized in the principal piece. The antibody staining was stronger in cauda epididymal sperm than in caput epididymal sperm, a finding consistent with the identification of TPI1 as a cauda epididymal sperm-enriched protein. Immunofluorescence with sodium dodecyl sulfate (SDS)-insoluble flagellar accessory structures showed a strong TPI1 signal only in the principal piece, indicating that TPI1 is a component of the fibrous sheath. Northern blot hybridization detected longer Tpi1 transcripts (1.56 kb) in mouse testis, whereas somatic tissues had shorter transcripts (1.32 kb). As there is only one triosephosphate isomerase gene in the mouse genome, we conclude that the three variants we see in sperm result from the use of alternative translation start codons in spermatogenic cells. Mol. Reprod. Dev. 80: 862–870, 2013. © 2013 The Authors. Published by Wiley Periodicals, Inc. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Chronic exercise training attenuates prostate cancer-induced molecular remodelling in the testis

“…Triosephosphate isomerase (Tpi1) is a member of the glycolytic pathway, and glutathione peroxidase 4 (Gpx4) is an essential antioxidant enzyme. Regarding Tpi1, protein expression data revealed two different molecular masses -26 and 31 KDa, which correspond, respectively, to a somatic cell isoform (sTpi1), previously detected in Sertoli and myoid cells, and a germ-cell specific isoform (gTpi1) [28,29]. Expression downregulation of gTpi1 was observed in PCa sedentary rats, compared with sedentary controls (p = 0.0087 -PCa+SED vs. CONT+SED).…”

TCTE1 is a conserved component of the dynein regulatory complex and is required for motility and metabolism in mouse spermatozoa

“…Glycolysis is a metabolic pathway that nets two molecules of ATP and pyruvate for every single molecule of glucose that is present in virtually all organisms. Interestingly, glycolysis has been shown to be crucial for producing ATP in mammalian spermatozoa (17,18,(49)(50)(51)(52)(53)(54)(55)(56)(57); thus, decreased glycolytic enzyme levels could be a reason for asthenozoospermia in Tcte1-null mice. To verify results of the TMT quantification, three glycolytic enzymes-hexokinase-2 (HK2), pyruvate kinase (PKM), and phosphoglycerate mutase 1 (PGAM1)-were evaluated using commercially available antibodies for Western blot analysis.…”

“…GAPDHS is the testis-specific ortholog of somatic GAPDH; in addition, there are other testis-specific glycolytic paralogues. Glycolysis is essential for motility because much of the ATP used by dynein is generated via the glycolytic pathway and not through the electron transport chain (17,18,(49)(50)(51)(52)(53)(54)(55)(56)(57). It is tempting to speculate that TCTE1 influences the glycolytic pathway; however, glycolysis is thought to occur at the fibrous sheath, as many glycolytic enzymes are covalently attached to that structure (40,57).…”

Proteomic markers of low and high fertility bovine spermatozoa separated by Percoll gradient

“…In bovine spermatozoa, glycolysis accounts for 20-44% of ATP production (Garrett, Revell, & Leese, 2008), with motility responsible for 75% of the total ATP consumption (Bohnensack & Halangk, 1986). In murine spermatozoa, TPI1 is restricted to the principal piece of the sperm flagellum and is tethered to the fibrous sheath (Ijiri et al, 2013). In the present study, if a lack of TPI1 is a limiting factor for ATP production required for optimum motility, this must reflect subtle variations as differences in TPI1 abundance were found between the two motility groups.…”