Extended Data Fig. 6: The addition of a (GS)2 tag accelerates nuclear import triggered by the addition of four (GS-amino acid-tag depends on the mechanical stability of the protein cargo.
From: Structural anisotropy results in mechano-directional transport of proteins across nuclear pores
(A) Left: Representative confocal images of U2OS cells 30 min in the recovery phase. Scale bar 10 µm. Right: Average time courses of the relative nucleus-to-cytoplasm localization of (upper) V13P and (GS)2-V13P; (middle) WT and (GS)2-WT; (lower) Y9P and (GS)2-Y9P. (B) Protein import rate constants (mean ± SEM) calculated from the accumulation curves. V13P (kI = 1.80 ± 0.09 ks−1, n = 160); (GS)2-V13P (kI = 1.90 ± 0.05 ks−1, n = 128); WT (kI = 1.62 ± 0.05 ks−1, n = 249); (GS)2-WT (kI = 1.83 ± 0.04 ks−1, n = 196); Y9P (kI = 1.09 ± 0.03 ks−1, n = 278); (GS)2-Y9P (kI = 1.34 ± 0.04 ks−1, n = 109). Significance levels for two-tailed Mann-Whitney non-parametric test **P ≤ 0.001, ***P ≤ 0.0001, ****P ≤ 0.0001. V13P vs. (GS)2-V13P, P = 8.98 × 10−3; WT vs. (GS)2-WT, P = 1.17 × 10−4; Y9P vs. (GS)2-Y9P, P = 4.34 × 10−5. (C) Plot of the percentage acceleration induced by the (GS)2 addition against the unfolding force of the Ig27 variants measured in AFM force-extension experiments (v = 400 nm/s). All points and bar plots indicate mean ± SEM.
