IST1 structures form at the nuclear membrane of cells cultured in collagen matrices. (A) Monocyte-derived dendritic cells (moDCs) seeded on top of collagen matrix. Cells were allowed to migrate into the matrix for 5 h. Shown are confocal z-sections and maximum intensity z-projections. Cells are labeled for IST1 (magenta). Green: phalloidin. Blue: DAPI. (B) Same as A, but now with FITC-labeled collagen (green in merge) and no phalloidin. Shown are orthogonal sections. Scale bars: 10 μm.