An intracellular signaling cassette characterized by the NIK-dependent processing and activation of NF-kappaB. Begins with activation of the NF-kappaB-inducing kinase (NIK), which in turn phosphorylates and activates IkappaB kinase alpha (IKKalpha). IKKalpha phosphorylates the NF-kappa B2 protein (
p100) leading to
p100 processing and release of an active NF-kappaB (
p52). The non-canonical NF-kappaB signaling pathway is generally activated by ligands of the TNF receptor superfamily, including lymphotoxin beta (LTB), CD40, OX40, RANK, TWEAK and B cell-activating factor (BAFF).