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532281 IRE1 Inhibitor IV, KIRA6 - Calbiochem


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Key Specifications Table

Empirical Formula


Catalog NumberPackaging Qty/Pack
5.32281.0001 Glass bottle 10 mg
OverviewA cell-permeable, bioavailable, non-toxic, imidazopyrazinyl-naphthalenyl-phenylurea based compound that acts as a potent, ATP-competitive, reversible, and selective inhibitor of IRE1α kinase (IC50 = 600 nM). Exhibits good selectivity over ERK2, JNK2, JNK3, PIM1, PAK4, and PKA (IC50 > 10 µM). Stabilizes the kinase domain of IRE1α in an inactive conformation and blocks its oligomerization and thereby reduces RNase domain activity. Shown to block brefeldin A-(Cat. Nos. 203729 & 500583) induced ER stress and apoptosis in INS-1 cells and tunicamycin (Cat. Nos. 654380 & 504570)-induced apoptosis in β-cells derived from C57BL/6 mice. Affords significant cytoprotection in combination with STF-083010 (Cat. No. 412510, 1 µM) and KIRA6 (50 nM). Systemic administration of KIRA6 in the Akita diabetic mice is shown to reduce their blood glucose levels, improve glucose tolerance, and conserve their β-cell function. Preserves photoreceptor function in a transgenic rat model (P23H) of chronic ER stress-induced retinal degeneration, when administered intravitreally. Displays desirable pharmacokinetic properties with t1/2 = 3.9 h and moderate clearance rate of 22.4 ml/min/kg in BABL/c mice (10 mg/kg, i.p.).

Please note that the molecular weight for this compound is batch-specific due to variable water content.
Catalogue Number532281
Brand Family Calbiochem®
Synonyms1-(4-(8-Amino-3-tert-butylimidazo[1,5-a]pyrazin-1-yl)naphthalen-1-yl)-3-(3-(trifluoromethyl)phenyl)urea, Kinase-Inhibiting RNase Attenuator 6, IRE1α Kinase Inhibitor
ReferencesGhosh, R., et al. 2014. Cell. 158, 534.
Product Information
FormOff-white to brown powder
Hill FormulaC₂₈H₂₅F₃N₆O
Chemical formulaC₂₈H₂₅F₃N₆O
Quality LevelMQ100
Biological Information
Primary TargetIRE1α kinase
Purity≥95% by HPLC
Physicochemical Information
Cell permeableY
Materials Information
Toxicological Information
Safety Information according to GHS
Safety Information
Product Usage Statements
Storage and Shipping Information
Ship Code Ambient Temperature Only
Toxicity Standard Handling
Storage +2°C to +8°C
Protect from Light Protect from light
Do not freeze Ok to freeze
Special InstructionsFollowing reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 6 months at -20°C.
Packaging Information
Packaged under inert gas Packaged under inert gas
Transport Information
Supplemental Information
Global Trade Item Number
Catalog Number GTIN
5.32281.0001 04055977260038


IRE1 Inhibitor IV, KIRA6 - Calbiochem SDS


Safety Data Sheet (SDS) 


Reference overview
Ghosh, R., et al. 2014. Cell. 158, 534.


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Technical Info

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Data Sheet

Note that this data sheet is not lot-specific and is representative of the current specifications for this product. Please consult the vial label and the certificate of analysis for information on specific lots. Also note that shipping conditions may differ from storage conditions.

Revision16-November-2016 JSW
Synonyms1-(4-(8-Amino-3-tert-butylimidazo[1,5-a]pyrazin-1-yl)naphthalen-1-yl)-3-(3-(trifluoromethyl)phenyl)urea, Kinase-Inhibiting RNase Attenuator 6, IRE1α Kinase Inhibitor
DescriptionA cell-permeable imidazopyrazinyl-naphthalenyl-phenylurea compound that acts as an IRE1α-selective type II kinase inhibitor (IC50 = 0.6 µM; IC50 >10 µM against Erk2, JNK2, JNK3, Pak4, Pim1, PKA) by targeting ATP-binding site in its inactive conformation. Stabilizing IRE1α kinase domain in an inactive conformation by KIRA6 prevents IRE1α oligomerization and subsequent RNase domain activity induction, resulting in effective inhibition against stress-induced cellular IRE1α oligomerization (5 mM DTT for 6 h +/1 µM KIRA6) & phosphorylation (1 h 10 µM; KIRA6 pretretament prior to 1 µM Tg/586005 & 586006 for 2 h), XBP1 mRNA splicing (IC50 = 2 µM; 1 h KIRA6 pretreatment prior to 0.5 µg/mL Tm/654380 & 504570 for 8 h), Ins1 mRNA degradation (IC50 = 0.5 µM; 1 hKIRA6 pretretament prior to 0.5 µg/mL Tm for 12 h), and apoptosis (% annexin V + cells = 22% vs. 60% post 72 h 0.25 µg/mL BFA/203729 & 500583 treatment with or without 0.5 µM KIRA6; No BFA control = 16%) in rat insulinoma INS-1 cultures without significant cytotoxicity (up to 10 µM for 72 h). Blockage of stress-induced apoptosis is similarly observed in primary human & murine islets cultures (0.5 µg/mL Tm for 16 h +/ 0.5 µM KIRA6) with a concomitant recovery of glucose-stimulated insulin secretion. KIRA6 is bioavailable via intraperitoneal injection in mice (Plasma Cmax/t1/2/AUC0-24 h = 3.3 µM/3.90 h/14.3 µM·h; 10 mg/kg BALB/c i.p.) in vivo with no apparent animal toxicity and is efficacious (5 or 10 mg/kg/12 h for 33 to 37 days) in reducing high blood glucose level due to chronic ER stress-induced β cell loss among Ins2+/Akita mice expressing proinsulin C96Y mutant with oxidative folding defect. Likewise, KIRA6 co-administration is shown to significantly reduce Rhodopsin mRNA degradation 96 h post Tm intraveal injection (2 µL per eye, final vitreal [Tm] & [KIRA6] = 20 µg/µL & 10 µM, respectively) in a rat model of acute photoreceptor loss in vivo, despite a rapid vitreal clearance (t1/2 <60 h). Synergistic cytoprotection is demonstrated when combined with STF-083010 (Cat. No. 412510) that covalently modifies IRE1 RNase domain Lys907 in Tm-treated INS-1 cultures.
FormOff-white to brown powder
Intert gas (Yes/No) Packaged under inert gas
Chemical formulaC₂₈H₂₅F₃N₆O
Purity≥95% by HPLC
SolubilityDMSO (50 mg/ml). Use only fresh DMSO for reconstitution.
Storage Protect from light
+2°C to +8°C
Do Not Freeze Ok to freeze
Special InstructionsFollowing reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 6 months at -20°C.
Toxicity Standard Handling
ReferencesGhosh, R., et al. 2014. Cell. 158, 534.