Biophysical Characterization of Interactions Involving Importin-α during Nuclear Import*
By B. Catimel, T. Teh, M. Fontes, I. Jennings, D. Jans, G. Howlett, E. Nice, Bostjan Kobe. Journal of Biological Chemistry, 2001
146 citations recorded by the source corpus.
Proteins containing the classical nuclear localization sequences (NLSs) are imported into the nucleus by the importin-α/β heterodimer. Importin-α contains the NLS binding site, whereas importin-β mediates the translocation through the nuclear pore. We characterized the interactions involving importin-α during nuclear import using a combination of biophysical techniques (biosensor, crystallography, sedimentation equilibrium, electrophoresis, and circular dichroism). Importin-α is shown to exist in a monomeric autoinhibited state (association with NLSs undetectable by biosensor). Association with importin-β (stoichiometry, 1:1; K D = 1.1 × 10−8 m) increases the affinity for NLSs; the importin-α/β complex binds representative monopartite NLS (simian virus 40 large T-antigen) and bipartite NLS (nucleoplasmin) with affinities (K D = 3.5 × 10−8 m and 4.8 × 10−8 m, respectively) comparable with those of a truncated importin-α lacking the autoinhibitory domain (T-antigen NLS, K D = 1.7 × 10−8 m; nucleoplasmin NLS,K D = 1.4 × 10−8 m). The autoinhibitory domain (as a separate peptide) binds the truncated importin-α, and the crystal structure of the complex resembles the structure of full-length importin-α. Our results support the model of regulation of nuclear import mediated by the intrasteric autoregulatory sequence of importin-α and provide a quantitative description of the binding and regulatory steps during nuclear import.
Subfields: Molecular Biology, Nutrition and Dietetics
View Paper: https://www.semanticscholar.org/paper/03cd49f96930227c681fcaabfd5d7d89a44274f3
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Molecular Biology
Citations in the corpus
- 14‐3‐3 suppresses the nuclear localization of threonine 157‐phosphorylated p27Kip1 (2004, background): “It is known that the affinity between importin a and NLS is dramatically increased in the presence of importin b (Catimel et al, 2001).”
- Molecular mechanism of the nuclear protein import cycle (2007, background): “Scanning Ala mutagenesis indicates that the Lys residue at position P2 is particularly important for this interaction, although positions P3 and P5 are also importan”
- Nuclear pore complex is able to transport macromolecules with diameters of about 39 nm. (2002, background): “Importin α binds to NP with a KD ~15 nM and importin ß binds to importin α with a KD ~40 nM (Catimel et al., 2001).”