protein
Aldo-keto reductase family 1 member C3
Gene
AKR1C3
Organism
Homo sapiens(9606)
Length
323 aa
Mass
36,853 Da
AKR1C3 (Aldo-keto reductase family 1 member C3) is a cytosolic enzyme that catalyzes NADPH-dependent reduction of ketosteroids to hydroxysteroids with broad substrate specificity (UniProt: P42330). It functions in classical and alternative androgen biosynthetic pathways, converting Δ4-androstenedione to testosterone and androsterone to 5α-androstane-3α,17β-diol, and also acts as a prostaglandin F2α synthase and estrogen metabolism enzyme, converting estrone to 17β-estradiol.
AKR1C3 participates in steroid hormone metabolism and prostaglandin signaling pathways. The enzyme's broad catalytic repertoire encompasses reduction of glucocorticoids, mineralocorticoids, and xenobiotic carbonyl compounds. UniProt reports no primary disease association annotation for this protein.
AKR1C3 is elevated in Alzheimer's disease brain tissue. Analysis of human post-mortem AD brain compared to age-matched controls using TMT-labeled quantitative proteomics across four subcellular fractions detected significant upregulation, with a mean log2 fold-change of 1.80 (Chaparral AD proteomics). This upregulation may reflect altered steroid or prostaglandin metabolism in AD pathology, though functional consequences remain to be determined.
Generated from the curated entity record below. May contain errors — verify against source links.
Proteomics Evidence · AD
↑ Up in ADP3
+1.798
P2
not detected
S2
not detected
S3
not detected
Mean log₂FC across detected fractions: +1.7978 (1 of 4 fractions detected)
Human post-mortem AD brain vs age-matched controls, TMT-labeled, 4 subcellular fractions (P2, P3, S2, S3), DDA proteomics.
Related Publications
Browse all →Tau molecular diversity contributes to clinical heterogeneity in Alzheimer's disease.
Dujardin Simon et al.Nature medicine2020PMID 32572268Deep Multilayer Brain Proteomics Identifies Molecular Networks in Alzheimer's Disease Progression.
Bai Bing et al.Neuron2020PMID 31926610A Multi-network Approach Identifies Protein-Specific Co-expression in Asymptomatic and Symptomatic Alzheimer's Disease.
Seyfried Nicholas T et al.Cell systems2017PMID 27989508Large-scale deep multi-layer analysis of Alzheimer's disease brain reveals strong proteomic disease-related changes not observed at the RNA level.
Johnson Erik C B et al.Nature neuroscience2022PMID 35115731Organization and regulation of gene transcription.
Cramer PatrickNature2019PMID 31462772
Function
Cytosolic aldo-keto reductase that catalyzes NADPH-dependent reduction of ketosteroids to hydroxysteroids. Displays broad substrate specificity with distinct positional and stereochemistry, primarily generating 17beta-hydroxysteroids, but also 3alpha- and 20alpha-hydroxysteroids (PubMed:10998348, PubMed:11165022, PubMed:20036328, PubMed:9415401, PubMed:9927279, PubMed:10998348, PubMed:9927279). Produces potent androgens via classical and 'backdoor'/alternative pathways. In the classical androgen metabolic pathway (biosynthesis of 5alpha-dihydrotestosterone (5alpha-DHT) via testosterone), catalyzes the reduction of delta4-androstenedione to form testosterone (PubMed:10998348, PubMed:11165022, PubMed:20036328, PubMed:9415401, PubMed:9927279). In the 'backdoor' androgen metabolic pathway (biosynthesis of 5alpha-dihydrotestosterone (5alpha-DHT) via pregnanes), reduces androsterone to 5alpha-androstane-3alpha,17beta-diol preceding 5alpha-DHT secretion (PubMed:10557352, PubMed:10998348, PubMed:9415401). Reduces 5alpha-DHT to less potent androgen 5alpha-androstane-3alpha,17beta-diol, likely regulating ligand availability for androgen receptors (PubMed:10557352, PubMed:10998348, PubMed:11165022, PubMed:14672942, PubMed:7650035, PubMed:9415401). May contribute to the metabolism of adrenal-derived androgen precursors. Reduces 11-keto-4-androstene-3,17-dione (11KA4) and 11-keto-5alpha-androstane-3,17-dione (11K-Adione) into potent androgens 11-ketotestosterone (11KT) and 11-ketodihydrotestosterone (11KDHT), respectively (PubMed:31926269). In estrogen metabolism, catalyzes the conversion of estrone to potent estrogen 17beta-estradiol (PubMed:10998348, PubMed:11165022, PubMed:20036328). Acts as a prostaglandin (PG) F2alpha synthase. Displays 11-ketoreductase and 9,11-endoperoxide reductase activities and reduces PGD2 to 11beta-PGF2alpha and PGH2 to PGF2alpha (PubMed:10622721, PubMed:11165022, PubMed:15047184, PubMed:19010934, PubMed:20036328, PubMed:7650035, PubMed:9415401, PubMed:9927279). Also displays retinaldehyde reductase activity toward 9-cis-retinal (PubMed:21851338). In vitro can efficiently catalyze bidirectional conversion between ketosteroids and hydroxysteroids using NADPH/NADP(+) or NADH/NAD(+) as cofactors. In vivo however, the reductase activity prevails since the major reducing cofactor NADPH inhibits NAD(+)-dependent oxidase activity (PubMed:11165022, PubMed:14672942). In addition, it is able to reduce in vitro various carbonyl compounds like menadione, phenanthrenequinone and nitrobenzaldehyde (By similarity)
Sources
Last updated 5/8/2026, 6:34:50 AM