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Human DCXR – another ‘moonlighting protein’ involved in sugar metabolism, carbonyl detoxification, cell adhesion and male fertility?
Author(s) -
Ebert Bettina,
Kisiela Michael,
Maser Edmund
Publication year - 2015
Publication title -
biological reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.993
H-Index - 165
eISSN - 1469-185X
pISSN - 1464-7931
DOI - 10.1111/brv.12108
Subject(s) - biology , sperm , reductase , aldo keto reductase , caenorhabditis elegans , biochemistry , metabolism , gamete , microbiology and biotechnology , genetics , enzyme , gene
Dicarbonyl/ l ‐xylulose reductase ( DCXR ; SDR20C1 ), a member of the short‐chain dehydrogenase/reductase ( SDR ) superfamily catalyzes the reduction of α‐dicarbonyl compounds and monosaccharides. Its role in the metabolism of l ‐xylulose has been known since 1970, when essential pentosuria was found to be associated with DCXR deficiency. Despite its early discovery, our knowledge about the role of human DCXR in normal physiology and pathophysiology is still incomplete. Sporadic studies have demonstrated aberrant expression in several cancers, but their physiological significance is unknown. In reproductive medicine, where DCXR is commonly referred to as ‘sperm surface protein P34H ’, it serves as marker for epididymal sperm maturation and is essential for gamete interaction and successful fertilization. DCXR exhibits a multifunctional nature, both acting as a carbonyl reductase and also performing non‐catalytic functions, possibly resulting from interactions with other proteins. Recent observations associate DCXR with a role in cell adhesion, pointing to a novel function involving tumour progression and possibly metastasis. This review summarizes the current knowledge about human DCXR and its orthologs from mouse and Caenorhabditis elegans ( DHS ‐21) with an emphasis on its multifunctional characteristics. Due to its close structural relationship with DCXR , carbonyl reductase 2 (Cbr2), a tetrameric enzyme found in several non‐primate species is also discussed. Similar to human DCXR , Cbr2 from golden hamster (P26h) and cow (P25b) is essential for sperm–zona pellucida interaction and fertilization. Because of the apparent similarity of these two proteins and the inconsistent use of alternative names previously, we provide an overview of the systematic classification of DCXR and Cbr2 and a phylogenetic analysis to illustrate their ancestry.