8h5b
The cryo-EM structure of nuclear transport receptor Kap114p complex with yeast TATA-box binding protein
Structural highlights
FunctionIMB5_YEAST Required for nuclear protein import and mediates docking of import substrate to distinct nucleoporins. Serves a receptor for nuclear localization signals. Mediates the nuclear import of TATA-binding protein (TBP) and of histones H2A and H2B.[1] [2] Publication Abstract from PubMedThe transcription factor TATA-box binding protein (TBP) modulates gene expression in nuclei. This process requires the involvement of nuclear transport receptors, collectively termed karyopherin-beta (Kap-beta) in yeast, and various regulatory factors. In previous studies we showed that Kap114p, a Kap-beta that mediates nuclear import of yeast TBP (yTBP), modulates yTBP-dependent transcription. However, how Kap114p associates with yTBP to exert its multifaceted functions has remained elusive. Here, we employ single-particle cryo-electron microscopy to determine the structure of Kap114p in complex with the core domain of yTBP (yTBP(C)). Remarkably, Kap114p wraps around the yTBP(C) N-terminal lobe, revealing a structure resembling transcriptional regulators in complex with TBP, suggesting convergent evolution of the two protein groups for a common function. We further demonstrate that Kap114p sequesters yTBP away from promoters, preventing a collapse of yTBP dynamics required for yeast responses to environmental stress. Hence, we demonstrate that nuclear transport receptors represent critical elements of the transcriptional regulatory network. Structural convergence endows nuclear transport receptor Kap114p with a transcriptional repressor function toward TATA-binding protein.,Liao CC, Wang YS, Pi WC, Wang CH, Wu YM, Chen WY, Hsia KC Nat Commun. 2023 Sep 8;14(1):5518. doi: 10.1038/s41467-023-41206-9. PMID:37684250[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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