I-kappaB/NF-kappaB complex

Definition

Target type: cellularcomponent

A protein complex containing an inhibitory-kappaB (I-kappaB/IKB) protein and one or more copies of an NF-kappaB protein. In the resting state, NF-kappaB dimers are bound to I-kappaB proteins, sequestering NF-kappaB in the cytoplasm. [GOC:bf, GOC:mah, PMID:9407099]

The IκB/NF-κB complex is a key regulator of gene expression in response to various stimuli, including inflammation, stress, and infection. The cellular component of this complex is composed of two main protein families: NF-κB and IκB.

NF-κB proteins are transcription factors that can activate the transcription of target genes by binding to specific DNA sequences. There are five different NF-κB proteins in mammals: p65 (RelA), RelB, c-Rel, p50 (NF-κB1), and p52 (NF-κB2). These proteins can form homo- or heterodimers.

IκB proteins are inhibitory proteins that bind to and sequester NF-κB proteins in the cytoplasm. The major IκB proteins are IκBα, IκBβ, and IκBε.

In resting cells, NF-κB proteins are bound to IκB proteins in the cytoplasm, which prevents NF-κB from entering the nucleus and activating gene transcription. Upon stimulation, IκB is phosphorylated by the IκB kinase (IKK) complex, leading to its ubiquitination and degradation by the proteasome. This allows NF-κB to translocate into the nucleus, where it can bind to DNA and activate the transcription of target genes.

The cellular localization of the IκB/NF-κB complex is dynamic and is regulated by various factors. In resting cells, the complex is predominantly located in the cytoplasm. Upon stimulation, the complex translocates to the nucleus, where it can activate gene transcription.

The cellular component of the IκB/NF-κB complex is essential for the regulation of a wide range of cellular processes, including inflammation, immunity, cell growth, and apoptosis. Dysregulation of this complex can lead to various diseases, such as cancer, autoimmune disorders, and inflammatory diseases.'
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Proteins (2)

Compounds (62)