title: Optineurin is required for CYLD-dependent inhibition of TNFα-induced NF-κB activation.
abstract: The nuclear factor kappa B (NF-κB) regulates genes that function in diverse cellular processes like inflammation, immunity and cell survival. The activation of NF-κB is tightly controlled and the deubiquitinase CYLD has emerged as a key negative regulator of NF-κB signalling. Optineurin, mutated in certain glaucomas and amyotrophic lateral sclerosis, is also a negative regulator of NF-κB activation. It competes with NEMO (NF-κB essential modulator) for binding to ubiquitinated RIP (receptor interacting protein) to prevent NF-κB activation. Recently we identified CYLD as optineurin-interacting protein. Here we have analysed the functional significance of interaction of optineurin with CYLD. Our results show that a glaucoma-associated mutant of optineurin, H486R, is altered in its interaction with CYLD. Unlike wild-type optineurin, the H486R mutant did not inhibit tumour necrosis factor α (TNFα)-induced NF-κB activation. CYLD mediated inhibition of TNFα-induced NF-κB activation was abrogated by expression of the H486R mutant. Upon knockdown of optineurin, CYLD was unable to inhibit TNFα-induced NF-κB activation and showed drastically reduced interaction with ubiquitinated RIP. The level of ubiquitinated RIP was increased in optineurin knockdown cells. Deubiquitination of RIP by over-expressed CYLD was abrogated in optineurin knockdown cells. These results suggest that optineurin regulates NF-κB activation by mediating interaction of CYLD with ubiquitinated RIP thus facilitating deubiquitination of RIP.
authors.affiliation: Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India.
authors.forename: Ananthamurthy
authors.initials: A
authors.lastname: Nagabhushana
authors.forename: Megha
authors.initials: M
authors.lastname: Bansal
authors.forename: Ghanshyam
authors.initials: G
authors.lastname: Swarup
mesh_terms: D018797:Cell Cycle Proteins; D000074749:Deubiquitinating Enzyme CYLD; D006367:HeLa Cells; D006801:Humans; D026901:Membrane Transport Proteins; D008954:Models, Biological; D050505:Mutant Proteins / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000378:metabolism; D035582:Transcription Factor TFIIIA / Q000737:chemistry / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D054875:Ubiquitination / Q000187:drug effects
chemical_list: D018797:Cell Cycle Proteins; D026901:Membrane Transport Proteins; D050505:Mutant Proteins; D016328:NF-kappa B; C409460:OPTN protein, human; D035582:Transcription Factor TFIIIA; D014409:Tumor Necrosis Factor-alpha; D025521:Tumor Suppressor Proteins; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; C409984:CYLD protein, human; D000074749:Deubiquitinating Enzyme CYLD