6AHO

Crystal structure of Kap114p

Summary for 6AHO

• Entry DOI: 10.2210/pdb6aho/pdb
• Descriptor: Importin subunit beta-5 (1 entity in total)
• Functional Keywords: karyopherin, tata box binding protein, transcription, nuclear transport, protein transport
• Biological source: Saccharomyces cerevisiae (Baker's yeast)
• Total number of polymer chains: 1
• Total formula weight: 114431.15

Authors

Liao, C.C.,Shankar, S.,Ahmed, G.R.,Hsia, K.C. (deposition date: 2018-08-20, release date: 2019-10-23, Last modification date: 2024-03-27)

Primary citation

Liao, C.C.,Shankar, S.,Pi, W.C.,Chang, C.C.,Ahmed, G.R.,Chen, W.Y.,Hsia, K.C.
Karyopherin Kap114p-mediated trans-repression controls ribosomal gene expression under saline stress.
Embo Rep., 21:-, 2020

PubMed Abstract: Nuclear accessibility of transcription factors controls gene expression, co-regulated by Ran-dependent nuclear localization and a competitive regulatory network. Here, we reveal that nuclear import factor-facilitated transcriptional repression attenuates ribosome biogenesis under chronic salt stress. Kap114p, one of the karyopherin-βs (Kap-βs) that mediates nuclear import of yeast TATA-binding protein (yTBP), exhibits a yTBP-binding affinity four orders of magnitude greater than its counterparts and suppresses binding of yTBP with DNA. Our crystal structure of Kap114p reveals an extensively negatively charged concave surface, accounting for high-affinity basic-protein binding. KAP114 knockout in yeast leads to a high-salt growth defect, with transcriptomic analyses revealing that Kap114p modulates expression of genes associated with ribosomal biogenesis by suppressing yTBP binding to target promoters, a trans-repression mechanism we attribute to reduced nuclear Ran levels under salinity stress. Our findings reveal that Ran integrates the nuclear transport pathway and transcription regulatory network, allowing yeast to respond to environmental stresses.

PubMed: 32484313
DOI: 10.15252/embr.201948324

Experimental method

X-RAY DIFFRACTION (2.502 Å)