Sigma-Aldrich Anti-Caspase-8 Clone Flice 4-1-20

Caspase-8 (UniProt: Q14790; also known as EC:3.4.22.61, CASP-8, Apoptotic cysteine protease, Apoptotic protease Mch-5, CAP4, FADD-homologous ICE/ced-3-like protease, FADD-like ICE, FLICE) is encoded by the CASP8 (also known as MCH5) gene (Gene ID: 841) in human. Caspase-8 is a member of a family of cysteine-requiring aspartate proteases that participate in the intracellular signaling cascade leading to apoptosis, or programmed cell death. Caspase-8 is recruited to death-inducing signaling complex (DISC), CD95 (Fas/APO-1) and tumor necrosis factor receptor 1 (TNFR1) and is therefore the most upstream caspase in the CD95 apoptotic pathway. Caspase-8 is ubiquitously expressed in various tissues, with highest expression in peripheral blood leukocytes, spleen, thymus and liver. Its barely detectable in brain, testis and skeletal muscle. It is mainly localized in the cytoplasm and upon activation, it can translocate to the membrane-associated DISC, where it undergoes proteolytic activation. It is synthesized as an inactive proenzyme composed of an N-terminal prodomain (aa 1-216) containing two death effector domains (DEDs), followed by a large (p18) (aa 217-374) and a small (p10) (aa 385-479) catalytic subunit. Caspase-8 that binds to the death effector domain (DED) of FADD through an analogous DED domain present in the proform of caspase-8. Active caspase-8 then proteolytically activates other downstream caspases including caspase-9, which lead to cell death. A total of 9 isoforms are known to be produced by alternative splicing. Studies show that only two of the FLICE isoforms (caspase-8/a and caspase-8/b) were predominantly expressed in cells of different origin. Both isoforms were recruited to the CD95 death-inducing signaling complex and were activated upon CD95 stimulation with similar kinetics. (Ref.: Scaffidi, C., et al. (1997). J Biol Chem. 272(43):26953-8; Tang, D., et al. (2000). J Biol Chem. 275(13):9303-7; Teitz, T., et al. (2000). Nat Med. 6(5):529-35; Chang, D.W., et al. (2002). EMBO J. 21(14):3704-14; Lavrik, I., et al. (2003). Cell Death Differ. 10(1):144-5; Schmitz, I., et al. (2004). J Immunol. 172(4):2194-200; Lavrik, I.N., et al. (2008). J Biol Chem. 283(39):26401-8; Kallenberger, S.M., et al. (2014). Sci Signal. 7(316):ra23; de Reuver, R. et al. (2022). Nature. 607(7920):784-789).

Full-length, recombinant human Caspase-8.

Quality Control Testing

Evaluated by Western Blotting in HepG2 cell lysate.

Western Blotting Analysis (WB): A 1:500 dilution of this antibody detected Caspase-8 in HepG2 cell lysate.

Tested Applications

Western Blotting Analysis: A representative lot detected Caspase-8 in Jurkat, Caco-2, and Daudi cell lysates.

Western Blotting Analysis: A representative lot detected Caspase-8 in Western Blotting application (Hung, J-C, et al. (2021). Cells. 10(11):2820).

Flow Cytometry Analysis: A representative lot detected Caspase-8 in Flow Cytometry application (Hartmann, B.M., et al. (2017). Nat Commun. 8(1):1931).

Note: Actual optimal working dilutions must be determined by end user as specimens, and experimental conditions may vary with the end user.

Clone FLICE 4-1-20 is a mouse monoclonal antibody that detects Caspase-8. It targets an epitope from the extracellular domain.

Purified mouse monoclonal antibody IgG1 in buffer containing 0.1 M Tris-Glycine (pH 7.4), 150 mM NaCl with 0.05% sodium azide.

0.5 mg/mL. Please refer to guidance on suggested starting dilutions and/or titers per application and sample type.

Recommended storage: +2°C to +8°C.

Concentration: Please refer to the Certificate of Analysis for the lot-specific concentration.

Unless otherwise stated in our catalog or other company documentation accompanying the product(s), our products are intended for research use only and are not to be used for any other purpose, which includes but is not limited to, unauthorized commercial uses, in vitro diagnostic uses, ex vivo or in vivo therapeutic uses or any type of consumption or application to humans or animals.