ZNF216 Is an A20-like and IkappaB kinase gamma-interacting inhibitor of NFkappaB activation.
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Huang J, Teng L, Li L, Liu T, Li L, Chen D, Xu LG, Zhai Z, Shu HB
ZNF216 Is an A20-like and IkappaB kinase gamma-interacting inhibitor of NFkappaB activation.
J Biol Chem. 2004 Apr 16;279(16):16847-53. Epub 2004 Jan 30.
- PubMed ID
- 14754897 [ View in PubMed]
- Abstract
The transcription factor NFkappaB plays important roles in immune regulation, inflammatory responses, and anti-apoptosis. Activation of NFkappaB requires the activity of IkappaB kinase, a kinase complex that contains two catalytic subunits, IKKalpha and IKKbeta, and a non-enzymatic regulatory subunit, IKKgamma. To understand how NFkappaB activation is regulated at the IKKgamma level, we searched for IKKgamma-interacting proteins by the yeast two-hybrid system. This search identified ZNF216, a zinc finger protein with unknown biological functions. ZNF216 contains an A20-like zinc finger domain (ZnF-A20) at its N terminus and an AN1-like domain (ZnF-AN1) at its C terminus. Similar to A20, ZNF216 interacted with IKKgamma, RIP, and TRAF6 in co-immunoprecipitation experiments. Domain mapping experiments indicated that the ZnF-A20 domain was responsible for interacting with IKKgamma and RIP, whereas the ZnF-AN1 domain interacted with TRAF6. ZNF216 inhibited NFkappaB activation triggered by overexpression of RIP and TRAF6 but not of p65. ZNF216 also inhibited tumor necrosis factor (TNF)-, interleukin-1-, and Toll-like receptor 4-induced NFkappaB activation in a dose-dependent manner. The ZnF-A20 domain was essential for ZNF216-mediated inhibition of NFkappaB activation. The ZnF-A20 and ZnF-AN1 domains of ZNF216 could interact with each other, whereas ZNF216 could form homo-oligomers or hetero-oligomers with A20. Unlike A20, which inhibits TNF-induced apoptosis, overexpression of ZNF216 sensitized cells to TNF-induced apoptosis. Our findings suggest that ZNF216 and A20 have redundant and distinct roles in regulating NFkappaB activation and apoptosis.