Non-canonical NF-κB signaling pathway. Simplified scheme of the non-canonica NF-κB signaling pathway. Nomenclature: RANKL: receptor activator of nuclear factor kappa-Β ligand; RANK: receptor activator of nuclear factor kappa-Β; TNFβ: tumor necrosis factor-beta, lymphotoxin; LTβR: lymphotoxin β-receptor; CD40L: cluster of differentiation 40 ligand, CD154, protein expressed on T-cells; CD40: cluster of differentiation 40, costimulatory protein on T-cells; BAFF: B-cell activating factor, tumor necrosis factor ligand superfamily member 13B; BAFFR: B-cell activating factor receptor; NIK: NF-κB inducing kinase; IKK complex: IκB kinase enzyme complex to upregulate the NF-κB signaling; IκBα: IκB kinase 1 (IKK1); IκBβ: IκB kinase 2 (IKK2); IκBγ: IκB kinase gamma; NEMO: NF-kappa-B essential modulator, regulatory scaffolding protein; P: phosphorylated; p100: NF-κB2 (p52) precursor protein; p52: NF-κB2; RelB: transcription factor RelB. Non-canonical NF-κB-IKK-complex is the inactive cytoplasmic form, consisting out of IκBα, p52 and RelB. The non-canonical NF-κB heterodimer is the active form entering into the nucleus consisting out of p52 and RelB.