Itch regulates p45/NF-E2 in vivo by Lys63-linked ubiquitination.
The hematopoietic-specific transcription factor p45/NF-E2 is an important transcriptional activator in the erythroid and megakaryocytic lineages. We describe the first in vivo evidence for the interaction between p45/NF-E2 and the E3 ubiquitin ligase Itch, and the subsequent ubiquitination of p45/NF-E2 by Itch. Interestingly, Itch suppressed the transactivation activity of p45/NF-E2 by adding a Lys63-linked polyubiquitin chain. Confocal microscopy revealed that ubiquitinated p45/NF-E2 became localized in the cytoplasm when Itch was over-expressed. Thus, Itch-mediated ubiquitination of p45/NF-E2 does not target the protein for proteasomal degradation, but instead retains p45/NF-E2 in the cytoplasm, where it cannot function as a transactivator. Finally, we suggest that this Itch-dependent p45/NF-E2 ubiquitination mechanism may regulate NF-E2 function during the development of hematopoietic cell lineages.
Lee
Tung-Liang
TL
Graduate Institute of Life Sciences, National Defense Medical Center, Neihu, Taipei 114, Taiwan, ROC.
Shyu
Yu-Chiau
YC
Hsu
Ting-Yin
TY
Shen
Che-Kun James
CK
D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism*; D006801:Humans; D008239:Lysine / Q000378:metabolism*; D050984:NF-E2 Transcription Factor, p45 Subunit / Q000235:genetics / Q000378:metabolism*; D025821:Polyubiquitin / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
D050984:NF-E2 Transcription Factor, p45 Subunit; D012097:Repressor Proteins; D025821:Polyubiquitin; C432966:ITCH protein, human; D044767:Ubiquitin-Protein Ligases; D008239:Lysine