Figure 3.

Syndecan‐4 crosstalks with α5β1 integrin to sense the fibrillarity and mechanical stiffness of FN. a,b) Adhesion forces of pKO‐β1 fibroblasts to heparin‐treated 2D globular FN substrates, 2.5D fibrillar FN matrices, and 3D fibrillar FN matrices a) without and b) with crosslinking. Reference adhesion forces of pKO‐β1 fibroblasts to non‐treated FN substrates or matrices are given in gray. Bottom p values compare given and reference data. Middle p values compare 2.5D fibrillar or 3D fibrillar FN matrices with 2D globular FN substrates. Top p values compare 2.5D fibrillar and 3D fibrillar FN matrices. AS indicates the slope of a linear regression and s.e. of adhesion strengthening rate (pN s⁻¹). c) Adhesion forces of pKO‐β1 fibroblasts depleted from syndecan‐1 (SDC1 KO), syndecan‐2 (SDC2 KO), syndecan‐3 (SDC3 KO), or syndecan‐4 (SDC4 KO) to 2D globular, 3D fibrillar, and crosslinked 3D fibrillar (3DX) FN substrates. Adhesion forces of pKO‐β1 fibroblasts to respective FN substrates are given in gray as reference. p values compare given and reference data. d) Adhesion forces of pKO‐β1 SDC4 KO fibroblasts rescued with syndecan‐4 to 2D globular, 3D fibrillar, and crosslinked 3D fibrillar (3DX) FN substrates. Adhesion forces of pKO‐β1 fibroblasts to respective FN substrates are given in gray as reference. Bottom p values compare given and reference data. Middle p values compare 2.5D fibrillar or 3D fibrillar FN matrices with 2D globular FN substrates. Top p values compare 2.5D fibrillar and 3D fibrillar FN matrices. Dots represent adhesion forces of individual fibroblasts and red bars the median. n indicates the number of fibroblasts tested. p values were calculated using two‐tailed Mann–Whitney test.