ZNF216 Is an A20-like and IkappaB kinase gamma-interacting inhibitor of NFkappaB activation.
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.
Huang
Jun
J
Department of Cell Biology and Genetics, College of Life Sciences, Peking University, Beijing 100871, China.
Teng
Lin
L
Li
Lixia
L
Liu
Ting
T
Li
Lianyun
L
Chen
Danying
D
Xu
Liang-Guo
LG
Zhai
Zhonghe
Z
Shu
Hong-Bing
HB
D017209:Apoptosis; D004268:DNA-Binding Proteins; D006801:Humans; D051550:I-kappa B Kinase; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B / Q000378:metabolism*; D009687:Nuclear Proteins; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3
D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D011506:Proteins; C114488:ZFAND5 protein, human; D017346:Protein Serine-Threonine Kinases; C496559:CHUK protein, human; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3