Catalog # IM4721

IκBα (cleavage specific) Antibody

Mouse Monoclonal

Application / Dilution

Size 100 μl

Species Reactivity Hu, Rt, Ms

MW 38 kDa

Isotype IgG1



The NF-κB/Rel transcription factors are present in the cytosol in an inactive state complexed with the inhibitory IκB proteins. Activation of IκBα occurs through both serine and tyrosine phosphorylation events. Activation through phosphorylation at Ser-32 and Ser-36 is followed by proteasome-mediated degradation, resulting in the release and nuclear translocation of active NF-κB. This pathway of IκBα regulation occurs in response to various NF-κB-activating agents, such as TNFα, interleukins, LPS, and irradiation. Alternatively, Tyr-42 phosphorylation in response to oxidative stress and growth factors leads to degradation of IκBα and increased NF-κB-activation. In contrast, Tyr-305 phosphorylation by c-Abl has been implicated in IκBα nuclear translocation and inhibition of NF-κB-activation. In addition, IκBα can be cleaved by caspases during apoptosis to produce an amino-terminal truncated IκBα (DN-IκBα). The DN-IκBα is resistant to degradation in response to inducers of NF-κB and acts as a dominant inhibitory molecule that suppresses NF-κB activity during apoptosis.


Waris et al. (2003) J Biol Chem 278(42):40778.
Reuther, J.Y. & Baldwin, Jr., A.S. (1999) J Biol Chem. 274: 20664.
Barkett, M. et al. (1997) J Biol Chem. 272: 29419.

Western blot showing IκBα cleavage in Jurkat cells that were untreated (lane 1) or treated with anti-Fas antibody for 30 mins. (lane 2). The blot was probed with mouse monoclonal IκBα (cleavage specific) antibody (IM4721).

Clone 5D1623 was generated from the caspase-3 mediated cleavage site of human IκBα. This sequence is well conserved in rat and mouse IκBα.

*For more information, see UniProt Accession P25963
Mouse monoclonal purified with protein G chromatography is supplied in 100μl phosphate-buffered saline containing 0.05% BSA and 0.05% sodium azide. Store at 4°C, stable for 6 months. For long term storage, aliquot and store at -20°C.

The products are are safely shipped at ambient temperature for both domestic and international shipments. Each product is guaranteed to match the specifications as indicated on the corresponding technical data sheet. Please store at -20C upon arrival for long term storage.

This antibody detects the 36 kDa* cleavage product of IκBα on SDS-PAGE immunoblots of human Jurkat cells treated with anti-Fas antibody for 30 mins. The antibody can be used to identify IκBα dominant inhibitory activity during apoptosis.

*All molecular weights (MW) are confirmed by comparison to Bio-Rad Rainbow Markers and to western blot mobilities of known proteins with similar MW.

This kit contains: