Supplementary Figure 1Examples of fluorescence images of SFs (A, D), nesprin 1 (B, E), and their merged images (C, F) on the apical and basal sides of SMCs, respectively, to confirm the distribution of nesprin 1, Bar = 10 µm.

Supplementary Figure 2Typical examples of fluorescent images of ACFs and nucleus in SMCs on glass (A–E) and the soft polyacrylamide gel (F–I) substrates. Nore that the higher magnification of nuclaus in dashed rectangle area in D shows a linear concentration of perinuclear DNA aligned the ACF (E, arrowheads). The frequency of cells showingACF (J), and the frequency of cells showing linear DNA concentrations (K) were also obtained and compared between the cells cultured on glass and the gel substrate. Bars = 20 µm.

P < 0.05

P < 0.05

Glass PA-gel(6 kPa)

Glass PA-gel(6 kPa)

J K

Freq

uenc

y of

cel

ls

show

ing

AC

Fs (%

)

Freq

uenc

y of

cel

ls

show

ing

DN

A-L

ine

(%)

Supplementary Figure 3Examples of fluorescent images of ACFs above the nucleus (A, D), nucleus (B, E), and BSFs underneath the nucleus (C, F). Scale bars = 10 µm. Dashed lines represent the direction of the nuclear major axis.

Supplementary Figure 4A typical example of fluorescent images of ACFs (A), BSFs (B), and nucleus (C) following treatment with the actin-sequestering drug latrunculin B (60 nM for 60 min). Dashed lines in A and B represent the outline of the nuclei. Note that ACFs showed much faster disassembly than BSFs during treatment with latrunculin B. Bar = 20 µm.