A splice variant of the C(2)H(2)-type zinc finger protein, ZNF268s, regulates NF-kappaB activation by TNF-alpha.
IkappaB kinase (IKK), the pivotal kinase in signal-dependent activation of nuclear factor-kappaB (NF-kappaB), is composed of multiple protein components, including IKK alpha/beta/gamma core subunits. To investigate the regulation of the IKK complex, we immunoaffinity purified the IKK complex, and by MALDI-TOF mass spectrometry identified a splice variant of zinc finger protein 268 (ZNF268) as a novel IKK-interacting protein. Both the full-length and the spliced form of the ZNF268 protein were detected in a variety of mammalian tissues and cell lines. The genes were cloned and expressed by in vitro transcription/translation. Several deletion derivatives, such as KRAB domain (KRAB) on its own, the KRAB/spacer/4-zinc fingers (zF4), and the spacer/ 4-zinc fingers (zS4), were ectopically expressed in mammalian cells and exhibited had different subcellular locations. The KRAB-containing mutants were restricted to the nucleus, while zS4 was localized in the cytosol. TNF-alpha-induced NF-kappaB activation was examined using these mutants and only zS4 was found to stimulate activation. Collectively, the results indicate that a spliced form of ZNF268 lacking the KRAB domain is located in the cytosol, where it seems to play a role in TNF-alpha-induced NF-kappaB activation by interacting with the IKK complex.
Chun
Jung Nyeo
JN
Division of Life and Pharmaceutical Sciences and Center for Cell Signaling Drug Discovery Research, Ewha Womans University, Seoul 127-750, Korea.
Song
In Sung
IS
Kang
Dong-Hoon
DH
Song
Hye Jin
HJ
Kim
Hye In
HI
Seo
Jawon
J
Suh
Ja Won
JW
Lee
Kong-Joo
KJ
Lee
Kong Ju
KJ
Kim
Jaesang
J
Kang
Sang Won
SW
D017398:Alternative Splicing; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000502:physiology*; D006801:Humans; D051550:I-kappa B Kinase / Q000502:physiology; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics* / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D016328:NF-kappa B; D012097:Repressor Proteins; D014409:Tumor Necrosis Factor-alpha; C482295:ZNF268 protein, human; D051550:I-kappa B Kinase