RelA Ser²⁷⁶ Phosphorylation Is Required for Activation of a Subset of NF-κB-Dependent Genes by Recruiting Cyclin-Dependent Kinase 9/Cyclin T1 Complexes

Abstract

Infectious and inflammatory stimuli induce expression of gene networks controlling proinflammatory and innate immune responses. One important arm of the inflammatory response is mediated by monocyte-derived tumor necrosis factor (TNF), a cytokine that activates gene expression programs in adjacent epithelial cells to propagate mucosal inflammation (42, 51). Here, the spectrum of functional activities and the magnitude and timing of TNF-induced gene expression are important determinants of tissue homeostasis. A central mediator of epithelial genomic response is nuclear factor-B (NF-B), an inducible transcription factor that controls the expression of proinflammatory genes and whose dysregulation has also been implicated in the pathogenesis of inflammatory, neoplastic, and autoimmune diseases (4,6,17).In most non-B-lymphoid cells, NF-B is sequestered as an inactive complex in the cytoplasm by the inhibitors of B (IBs). The mechanism by which NF-B is activated by TNF, referred to as the "canonical" activation pathway, has been extensively investigated (22). The canonical pathway is activated by ligands of the TNF superfamily including TNF alpha, the prototypical macrophage-derived cytokine that binds to the ubiquitously expressed TNF receptor 1 (TNFRI) (50). TNFinduced TNFRI trimerization induces the recruitment of cytoplasmic signal adapters, including the TNF receptor-associated death domain (TRADD), TNF receptor-associated factor 2 (TRAF2) and TRAF6, receptor-interacting protein (RIP), mitogen/extracellular signal-regulated kinase kinase 3, and others (23)(24)(25). This activated submembranous TNFRI complex transiently recruits the IB kinase (IKK) complex, resulting in the phosphorylation of the catalytic IKK␣ and -␤ kinases followed by its cytosolic release (15,43). In the cytosol, activated IKK phosphorylates serine (Ser) residues 32 and 36 on the NH2 terminal regulatory domain of IB␣, targeting IB␣ for proteolytic destruction by ubiquitination and calpain pathways

Site-specific Phosphorylation of the p65 Protein Subunit Mediates Selective Gene Expression by Differential NF-κB and RNA Polymerase II Promoter Recruitment

“…Several studies have shown that reconstitution of p65-deficient mouse embryonic fibroblasts with p65 S205A, S276A, S281A, T435A, S468A, and S536A mutants leads to reduction of NF-B transcriptional activity confined to certain genes (12,20,(22)(23)(24)(25). Also, loss of glycogen synthase kinase-3␤ (GSK-3␤), which phosphorylates p65 at Ser-468 (26), has profound effects on the expression of interleukin-6 (IL-6) and chemokine (CC motif) ligand 2 (CCL2) genes, but it only minimally impacts IB␣ (NFKBIA) and chemokine (CXC motif) ligand 2 (CXCL2) expression (27).…”

Breakpoint Cluster Region–Mediated Inflammation Is Dependent on Casein Kinase II

“…CK2 forms a heterocomplex composed of two catalytic a subunits and two regulatory subunits (9). It was reported that CK2 phosphorylates p65 (10)(11)(12), an action critical for NF-kB-mediated transcription (13,14), although a detailed molecular mechanism of how CK2 regulates the transcription has not been shown.…”

Curcumin mitigates cerebral vasospasm and early brain injury following subarachnoid hemorrhage via inhibiting cerebral inflammation

“…As one of the most abundant and well‐characterized NF‐κB dimer, P65 (RelA) translocate to nuclear and drive transcriptional response (Hayden & Ghosh, 2008; Karin & Ben‐Neriah, 2000; Vallabhapurapu & Karin, 2009). Phosphorylated form of P65/RelA is specifically required to activate transcriptional responses, including inflammatory response (Jamaluddin, Wang, Boldogh, Tian, & Brasier, 2007; Nicodeme et al., 2010; Nowak et al., 2008; Vermeulen, De Wilde, Van Damme, Vanden Berghe, & Haegeman, 2003; Zhong, SuYang, Erdjument‐Bromage, Tempst, & Ghosh, 1997). In this study, phosphorylated P65 was detected to be significantly up‐regulated following SAH induction.…”