Nuclear factor NF-kappa-B, p105 subunit (IPR030503)

Short name: NF-kB_p105

Overlapping homologous superfamilies


Family relationships


This entry represents the NF-kappaB subunit precursor p105, which can undergo cotranslational processing by the 26S proteasome to produce a 50 kDa protein (p50). p50 is a DNA binding subunit of the NF-kappaB (NF-kappaB) protein complex [PMID: 9450761].

NF-kappaB is a pleiotropic transcription factor present in almost all cell types. It is the endpoint of a series of signal transduction events that are initiated by a vast array of stimuli related to many biological processes such as inflammation, immunity, differentiation, cell growth, tumorigenesis and apoptosis. NF-kappaB is a homo- or heterodimeric complex formed by the Rel-like domain-containing proteins RelA/p65, RelB, NFKB1/p50, c-Rel and NFKB2/p52 [PMID: 22302935]. Each individual NF-kappaB subunit, and perhaps each dimer, carries out unique functions in regulating transcription. Dimer-specific functions can be conferred by selective protein-protein interactions with other transcription factors, coregulatory proteins, and chromatin proteins [PMID: 22435556].

NF-kB1 and NF-kB2 are synthesised as large precursors, called p105 and p100, which undergo processing to generate the NF-kB subunits p50 and p52, respectively [PMID: 9597130]. The processing of p105 and p100 is mediated by the ubiquitin/proteasome pathway, and involves selective degradation of their C-terminal regions containing ankyrin repeats [PMID: 10837071]. Unlike RelA, RelB and c-Rel, p50 and p52 do not contain transactivation domains in their C-termini. Nevertheless, they play critical roles in modulating the specificity of NF-kB function [PMID: 12360211].

GO terms

Biological Process

GO:0006357 regulation of transcription by RNA polymerase II

Molecular Function

GO:0003700 DNA-binding transcription factor activity

Cellular Component

GO:0005737 cytoplasm
GO:0005634 nucleus

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.