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Abstract #46299 Published in IGR 13-2
Optineurin is required for CYLD-dependent inhibition of TNF(alpha)-induced NF-(kappa)B activation
Nagabhushana A; Bansal M; Swarup GPLoS ONE 2011; 6: e17477
The nuclear factor kappa B (NF-(kappa)B) regulates genes that function in diverse cellular processes like inflammation, immunity and cell survival. The activation of NF-(kappa)B is tightly controlled and the deubiquitinase CYLD has emerged as a key negative regulator of NF-(kappa)B signalling. Optineurin, mutated in certain glaucomas and amyotrophic lateral sclerosis, is also a negative regulator of NF-(kappa)B activation. It competes with NEMO (NF-(kappa)B essential modulator) for binding to ubiquitinated RIP (receptor interacting protein) to prevent NF-(kappa)B 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 (alpha) (TNF(alpha))-induced NF-(kappa)B activation. CYLD mediated inhibition of TNF(alpha)-induced NF-(kappa)B activation was abrogated by expression of the H486R mutant. Upon knockdown of optineurin, CYLD was unable to inhibit TNF(alpha)-induced NF-(kappa)B 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-(kappa)B activation by mediating interaction of CYLD with ubiquitinated RIP thus facilitating deubiquitination of RIP.
G. Swarup. Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India. Email: gshyam@ccmb.res.in
Classification:
3.4.2 Gene studies (Part of: 3 Laboratory methods > 3.4 Molecular genetics)
3.6 Cellular biology (Part of: 3 Laboratory methods)
