M. Klinkenberg et al., Functional redundancy of the zinc fingers of A20 for inhibition of NF-kappa B activation and protein-protein interactions, FEBS LETTER, 498(1), 2001, pp. 93-97
The turner necrosis factor (TNF) inducible protein A20 is a potent inhibito
r of nuclear factor-kappaB (I kappaB)-mediated gene expression in response
to TNF and several other stimuli. The C-terminal domain of A20 is character
ized by seven zinc finger structures. Here, we show that a minimum of four
zinc fingers is required to inhibit TNF-induced nuclear factor-kappaB (NF-k
appaB) activation to a level that is comparable to that obtained with the w
ild-type A20 protein. However, there was no strict requirement for a partic
ular zinc finger structure, since a mutant A20 protein containing only the
first four zinc fingers was as potent as a mutant protein containing only t
he last four zinc fingers. A similar functional redundancy of the A20 zinc
fingers was also observed for binding of A20 to a number of other proteins,
including two novel NF-kappaB inhibitory proteins (ABIN-1, ABIN-2), A20 it
self, the anti-apoptotic protein TXBP151, and a regulatory component of the
I kappaB kinase complex, IKK gamma. R Moreover, me demonstrate that comple
te loss of binding of any of these proteins correlates with complete loss o
f A20's ability to inhibit TNF-induced NF-kappaB activation, However, bindi
ng of IKK gamma as such is not sufficient for inhibition of NF-kappaB depen
dent gene expression in response to TNF, (C) 2001 Federation of European Bi
ochemical Societies. Published by Elsevier Science B,V, All rights reserved
.