4TNM

Crystal structure of Arabidopsis importin-alpha3 armadillo repeat domain

4TNM の概要

• エントリーDOI: 10.2210/pdb4tnm/pdb
• 分子名称: Importin subunit alpha (1 entity in total)
• 機能のキーワード: armadillo repeat, protein binding
• 由来する生物種: Arabidopsis thaliana (Mouse-ear cress)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 58669.91

構造登録者

Wirthmueller, L.,Banfield, M. (登録日: 2014-06-04, 公開日: 2014-10-08, 最終更新日: 2023-12-27)

主引用文献

Wirthmueller, L.,Roth, C.,Fabro, G.,Caillaud, M.C.,Rallapalli, G.,Asai, S.,Sklenar, J.,Jones, A.M.,Wiermer, M.,Jones, J.D.,Banfield, M.J.
Probing formation of cargo/importin-alpha transport complexes in plant cells using a pathogen effector.
Plant J., 81:40-52, 2015

PubMed Abstract: Importin-αs are essential adapter proteins that recruit cytoplasmic proteins destined for active nuclear import to the nuclear transport machinery. Cargo proteins interact with the importin-α armadillo repeat domain via nuclear localization sequences (NLSs), short amino acids motifs enriched in Lys and Arg residues. Plant genomes typically encode several importin-α paralogs that can have both specific and partially redundant functions. Although some cargos are preferentially imported by a distinct importin-α it remains unknown how this specificity is generated and to what extent cargos compete for binding to nuclear transport receptors. Here we report that the effector protein HaRxL106 from the oomycete pathogen Hyaloperonospora arabidopsidis co-opts the host cell's nuclear import machinery. We use HaRxL106 as a probe to determine redundant and specific functions of importin-α paralogs from Arabidopsis thaliana. A crystal structure of the importin-α3/MOS6 armadillo repeat domain suggests that five of the six Arabidopsis importin-αs expressed in rosette leaves have an almost identical NLS-binding site. Comparison of the importin-α binding affinities of HaRxL106 and other cargos in vitro and in plant cells suggests that relatively small affinity differences in vitro affect the rate of transport complex formation in vivo. Our results suggest that cargo affinity for importin-α, sequence variation at the importin-α NLS-binding sites and tissue-specific expression levels of importin-αs determine formation of cargo/importin-α transport complexes in plant cells.

PubMed: 25284001
DOI: 10.1111/tpj.12691

実験手法

X-RAY DIFFRACTION (2.9 Å)