ProRS Inhibitor; Halofuginone

Biochem/physiol Actions

Primary Targetprolyl-tRNA synthetase

General description

A cell-permeable racemic mixture of Halofuginone whose D-(+)/(2R, 3S) enantiomer serves as the active inhibitor against ProRS-mediated aminoacylation by simultaneously preventing ProRS-catalyzed Pro-AMP formation and the subsequent Pro transfer from Pro-AMP to tRNA^Pro. Proline, but not other NEAA, is able to reverse the inhibitory effect of HF in in vitro rabbit reticulocyte lysate translations (1 µM HF; 1 mM Pro) and prevent HF-induced cellular AAR pathway activation (100 nM HF/2 mM Pro/MEF; 10 nM HF/1 mM Pro/Murine CD4⁺ CD25^- T cells). Shown to inhibit bFGF-induced neovascularization in a murine corneal angiogenesis model (5 mg/kg/d via food intake) and significantly reduce the severity of MOG33-55-induced EAE in mice (2 µg/mouse/d i.p.) in vivo. Unlike AA-AMP mimetics, HF does not compete against ATP for ProRS binding.

A cell-permeable racemic mixture of Halofuginone, a halogenated derivative of the Dichroa febriguga alkaloid Febrifugine, whose D-(+)/(2R, 3S) enantiomer serves as the active inhibitor against ProRS- (prolyl-tRNA synthetase) mediated aminoacylation by simultaneously targeting/blocking ProRS Proline-binding pocket with its hydroxypiperidine and tRNA 3′ end adenosine-binding site with its halogenated 4-quinazolinone, preventing not only ProRS-catalyzed prolyl adenylation (Pro-AMP formation), but also the subsequent Pro transfer from Pro-AMP to tRNA^Pro. Consistently, only proline, but not other NEAA, is able to reverse the inhibitory effect of HF in in vitro rabbit reticulocyte lysate translations (1 µM HF; 1 mM Pro) and prevent HF-induced cellular AAR (amino acid response) pathway activation (100 nM HF/2 mM Pro/MEF; 10 nM HF/1 mM Pro/Murine CD4⁺ CD25^- T cells). Shown to inhibit bFGF-induced neovascularization in a murine corneal angiogenesis model (5 mg/kg/day via food intake) and significantly reduce the severity of myelin antigen MOG33-55-induced autoimmune EAE/encephalomyelitis in mice (2 µg/mouse/day i.p.) in vivo. Unlike AA-AMP mimetics, HF does not compete against ATP for ProRS binding. ATP, in its ProRS bound state, actually helps stabilize HF via hydrogen bond interactions.

Legal Information

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Other Notes

Zhou, H., et al. 2013, Nature494, 121.r>Keller, T.L., et al. 2012, Nat. Chem. Biol.12, 311.r>Sundrud, M.S., et al. 2009, Science324, 1334.Elkin, M., et al. 2000, FASEB J.14, 2477.Elkin, M., et al. 1999, Clin. Cancer Res.5, 1982.

Packaging

Packaged under inert gas

10 mg in Glass bottle

Reconstitution

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 3 months at -20°C.

Warning

Toxicity: Standard Handling (A)