A new MIF4G domain-containing protein, CTIF, directs nuclear cap-binding protein CBP80/20-dependent translation
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- Title
- A new MIF4G domain-containing protein, CTIF, directs nuclear cap-binding protein CBP80/20-dependent translation
- Authors
- Kim, KM; Cho, H; Choi, K; Kim, J; Kim, BW; Ko, YG; Jang, SK; Kim, YK
- Date Issued
- 2009-09
- Publisher
- COLD SPRING HARBOR LAB PRESS, PUBLICATIONS DEPT
- Abstract
- During or right after mRNA export via the nuclear pore complex (NPC) in mammalian cells, mRNAs undergo translation mediated by nuclear cap-binding proteins 80 and 20 (CBP80/20). After CBP80/20-dependent translation, CBP80/20 is replaced by cytoplasmic cap-binding protein eIF4E, which directs steady-state translation. Nonsense-mediated mRNA decay (NMD), one of the best-characterized mRNA surveillance mechanisms, has been shown to occur on CBP80/20-bound mRNAs. However, despite the tight link between CBP80/20-dependent translation and NMD, the underlying molecular mechanism and cellular factors that mediate CBP80/20-dependent translation remain obscure. Here, we identify a new MIF4G domain-containing protein, CTIF (CBP80/20-dependent translation initiation factor). CTIF interacts directly with CBP80 and is part of the CBP80/20-dependent translation initiation complex. Depletion of endogenous CTIF from an in vitro translation system selectively blocks the translation of CBP80-bound mRNAs, while addition of purified CTIF restores it. Accordingly, down-regulation of endogenous CTIF abrogates NMD. Confocal microscopy shows that CTIF is localized to the perinuclear region. Our observations demonstrate the existence of CBP80/20-dependent translation and support the idea that CBP80/20-dependent translation is mechanistically different from steady-state translation through identification of a specific cellular protein, CTIF.
- Keywords
- CTIF; nonsense-mediated mRNA decay; nuclear cap-binding protein CBP80/20; eukaryotic translation initiation factor 4G; steady-state translation; MESSENGER-RNA DECAY; NONSENSE-MEDIATED DECAY; EXON JUNCTION COMPLEX; MAMMALIAN-CELLS; POLY(A)-BINDING PROTEIN; QUALITY-CONTROL; SURVEILLANCE; INITIATION; UPF1; TRANSCRIPTS
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/26100
- DOI
- 10.1101/GAD.1823409
- ISSN
- 0890-9369
- Article Type
- Article
- Citation
- GENES & DEVELOPMENT, vol. 23, no. 17, page. 2033 - 2045, 2009-09
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