Gene Ontology annotation through association of InterPro records with GO terms.
Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity.
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
Automated transfer of experimentally-verified manual GO annotation data to mouse-rat orthologs.
Combined Automated Annotation using Multiple IEA Methods.
Role of endogenous regucalcin in protein tyrosine phosphatase regulation in the cloned rat hepatoma cells (H4-II-E).
Regulatory role of endogenous regucalcin in the enhancement of nuclear deoxyribonuleic acid synthesis with proliferation of cloned rat hepatoma cells (H4-II-E).
Role of endogenous regucalcin in bone metabolism: bone loss is induced in regucalcin transgenic rats.
Role of endogenous regucalcin in nuclear regulation of regenerating rat liver: suppression of the enhanced ribonucleic acid synthesis activity.
Inhibitory role of regucalcin in the regulation of nitric oxide synthase activity in rat brain cytosol: involvement of aging.
Calcium-binding protein regucalcin increases calcium-independent proteolytic activity in rat liver cytosol.
Overexpression of regucalcin suppresses apoptotic cell death in the cloned rat hepatoma H4-II-E cells induced by a naturally occurring isothiocyanate sulforaphane.
Overexpression of regucalcin suppresses cell proliferation of cloned normal rat kidney proximal tubular epithelial NRK52E cells.
Overexpression of regucalcin suppresses apoptotic cell death in cloned normal rat kidney proximal tubular epithelial NRK52E cells: change in apoptosis-related gene expression.
Senescence marker protein 30 functions as gluconolactonase in L-ascorbic acid biosynthesis, and its knockout mice are prone to scurvy.
Regucalcin increases Ca2+-ATPase activity in the heart mitochondria of normal and regucalcin transgenic rats.
Overexpression of regucalcin enhances glucose utilization and lipid production in cloned rat hepatoma H4-II-E cells: Involvement of insulin resistance.
Inhibitory effect of calcium-binding protein regucalcin on Ca2(+)-activated DNA fragmentation in rat liver nuclei.
Effect of calcium-binding protein regucalcin on hepatic protein synthesis: inhibition of aminoacyl-tRNA synthetase activity.
Sperm parameters and epididymis function in transgenic rats overexpressing the Ca2+-binding protein regucalcin: a hidden role for Ca2+ in sperm maturation?
Purification of calcium binding substance from soluble fraction of normal rat liver.
Enhanced expression of calcium-binding protein regucalcin mRNA in regenerating rat liver.
Gene regulation of senescence marker protein-30 (SMP30): coordinated up-regulation with tissue maturation and gradual down-regulation with aging.
Expression of calcium-binding protein regucalcin mRNA in fetal rat liver is stimulated by calcium administration.
Falcon (Edison Scientific) deep research report on rat Rgn (regucalcin / SMP-30 / gluconolactonase, UniProt Q03336)
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The core biochemical function of rat Rgn is a metal-dependent gluconolactonase
(EC 3.1.1.17) with a six-bladed beta-propeller fold whose central cavity
coordinates a divalent metal at the active site (Glu18, Asn154, Asp204, with
Asn103 important for catalysis).
"1. **Primary biochemical function:** Rat Rgn encodes regucalcin/SMP30, a **metal-dependent gluconolactonase/lactonase (EC 3.1.1.17)** with a **six-bladed β‑propeller** active site coordinating a divalent metal (Glu18/Asn154/Asp204; Asn103 important for catalysis)."
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In non-primate mammals SMP30/GNL supports ascorbic acid (vitamin C) biosynthesis
by forming the gamma-lactone ring from L-gulonate, and SMP30/GNL knockout mice
develop scurvy on vitamin C-deficient diets.
"**Ascorbate/vitamin C pathway role (in non‑primates):** SMP30/GNL is implicated in the ascorbic acid biosynthesis pathway by catalyzing formation of the **γ‑lactone ring** from **L‑gulonate** (i.e., producing **L‑gulono‑γ‑lactone**, which is then converted to ascorbic acid by downstream enzymes). Genetic/physiological support includes **SMP30/GNL knockout mice** developing **scurvy** on vitamin C‑deficient diets."
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The enzyme requires a divalent metal ion (Zn2+ and Mn2+ cited as activators)
and hydrolyzes multiple aldonolactones in vitro, including D/L-glucono-,
gulono-, and galactono-lactones.
"A central, experimentally supported biochemical activity of regucalcin/SMP30 is **gluconolactonase (EC 3.1.1.17)** activity, requiring a **divalent metal ion** (e.g., **Zn2+** and **Mn2+** are cited as activators) and showing activity on multiple **aldonolactones** in vitro (e.g., D/L‑glucono‑γ‑lactone, D/L‑gulono‑γ‑lactone, D/L‑galactono‑γ‑lactone)."
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Regucalcin is a multifunctional Ca2+-signaling regulator that is explicitly NOT
an EF-hand protein; it acts as a cytoplasmic regulator capable of nuclear
translocation, inhibiting kinases/phosphatases and DNA/RNA/protein synthesis,
thereby influencing cell-cycle progression and apoptosis sensitivity.
"Regucalcin is also widely described as a **multifunctional Ca2+-signaling regulator** (not an EF‑hand protein), acting as a cytoplasmic regulator and capable of **nuclear translocation**, with inhibitory effects on multiple kinases/phosphatases and on DNA/RNA/protein synthesis, thereby influencing cell-cycle progression and apoptosis sensitivity in various rat cell systems."
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A 2023 review positions regucalcin as a multifunctional suppressor that localizes
in cytoplasm and nucleus, maintains intracellular Ca2+ homeostasis by activating
Ca2+ pumps in the plasma membrane, mitochondria, and ER, and inhibits multiple
enzymes including aminoacyl-tRNA synthetase, nitric oxide synthase, cysteinyl
protease, and DNA/RNA synthesis and cell-cycle progression.
"Positions regucalcin as a multifunctional suppressor that localizes in cytoplasm and nucleus; maintains intracellular Ca2+ homeostasis by activating Ca2+ pumps in plasma membrane, mitochondria, and ER; inhibits kinases, phosphatases, nitric oxide synthase, cysteinyl protease, aminoacyl-tRNA synthetase, DNA/RNA synthesis, and cell-cycle progression; summarizes rat liver, kidney, prostate, and hepatoma studies showing anti-proliferative and homeostatic roles"
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Under ascorbate deficiency, SMP30 increases in serum extracellular vesicles,
indicating an extracellular/secreted-vesicular compartment for SMP30 under
stress conditions, in addition to its primary cytoplasmic/nuclear localization.
"Ascorbate deficiency increases SMP30 in serum EVs, indicating an extracellular/secreted-vesicular compartment for SMP30 under stress conditions."