Dicarbonyl L-Xylulose Reductase (DCXR), a “Moonlighting Protein” in the Bovine Epididymis

Abstract

During maturation and the acquisition of their fertilization potential, male germ cells are subjected to various sequential modifications that occur in the epididymis. Protein addition, reorganization or withdrawal, comprise some of these modifications. Dicarbonyl L-xylulose reductase (DCXR), a multifunctional protein involved in various enzymatic and protein interaction processes in different physiological systems, is one of the proteins added to spermatozoa in the epididymis. DCXR is a well-conserved protein with multiple characteristics including enzymatic activities and mediation of cell-cell interaction. In this study, we characterized the DCXR gene and protein expression in the bovine epididymis. Dicarbonyl L-xylulose reductase mRNA is differentially expressed in the caput, corpus, and cauda epididymide epithelial cells with a higher level observed in the cauda region. Tissue protein expression follows the same pattern as the corresponding mRNA expression with a cytoplasmic and apical distribution in the corpus and cauda epithelial cells, respectively. The protein can also be found with a nuclear localization in cauda epididymidis epithelial cells. Dicarbonyl L-xylulose reductase is secreted in the epididymis luminal compartment in the soluble fraction and is associated with microvesicular elements named epididymosomes. In spermatozoa, the DCXR protein was found in the cytoplasmic and membranous fractions. Expression of the DCXR protein is higher on caput spermatozoa but finally shows a weak detection in semen. These data describe DCXR in the bovine epididymis and reveal that its behavior differs from that found in humans. It seems that, in this model, the DCXR protein might have a questionable involvement in the fertilization process.

Changes in Protein O-GlcNAcylation During Mouse Epididymal Sperm Maturation

“…The mechanisms by which OGT is lost from sperm during epididymal transit is still unknown. Most reports indicate that proteins are incorporated to sperm during maturation (reviewed in Gervasi and Visconti, 2017 ), however the protein dicarbonyl L-xylulose reductase (DCXR) has been reported to be selectively removed from bovine sperm during maturation (Akintayo et al, 2015 ). Our data suggest that OGT is lost from the sperm flagellum during transit through the epididymis, and further investigations are necessary to determine whether it is due to the specific degradation of this transferase.…”

Fluoride Interferes with the Sperm Fertilizing Ability via Downregulated SPAM1, ACR, and PRSS21 Expression in Rat Epididymis

“…The epididymis was an important reproductive organ that is responsible for transmission, concentration, and storage of sperm in male mammals. , Spermatozoa attain fertilization ability after undergoing a series of structural and functional alterations in the epididymis. ,, Therefore, we first observed the morphological features of the epididymal luminal epithelial cells after fluoride exposure. The results of the current study revealed that fluoride exposure led to the loss of nuclei in epithelial cells.…”

Molecular Markers: A New Paradigm in the Prediction of Sperm Freezability

“…Finally, proteomic profiling of frozen–thawed human spermatozoa [ 101 ] unraveled a significant upregulation of several proteins including clusterin (CLU) as a major sperm glycoprotein [ 133 ], tektin (TEKT) 2 and 3 present in the axoneme and periaxonemal structures necessary for progressive motility of spermatozoa [ 134 ], and L-xylulose reductase (DCXR), a multifunctional protein involved in various enzymatic and protein interaction processes [ 135 ]. On the other hand, proteins such as acrosin (ACR), the major proteinase present in the acrosome of mature spermatozoa [ 136 ], calmodulin (CALM1) involved in calcium signal transduction pathways [ 137 ], cytochrome (CYC2), and NADH-cytochrome b5 reductase2 (CYB5R2) as critical elements involved in sperm mitochondrial biogenesis and metabolism [ 138 , 139 ] were significantly decreased following cryopreservation, resulting in reduced post-thaw semen quality.…”