Adhesion and spreading of Tln1^3mutmacrophages are not impaired despite reduced levels of integrin activation. (A) Expression levels of Talin1, RIAM, Kindlin-3, and Rap1 in WT and Tln1^3mut macrophages assessed by western blotting. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) served as loading control. (B) Surface expression of integrin β1, β2, and β3 of WT (red) and Tln1^3mut (blue) macrophages shown in representative FACS blots. (C) Static adhesion of Tln1^3mut compared with WT macrophages on fibronectin, vitronectin, ICAM-1, and VCAM-1 (n = 6 experiments; cells isolated from 3 mice per genotype). (D) Spreading of WT and Tln1^3mut macrophages on fibronectin and ICAM-1 (n = 6 experiments; cells isolated from 3 mice per genotype). (E-F) Quantification of total (E) and 9EG7⁺ (F) β1 integrin staining intensity in regions of clustered integrins in WT and Tln1^3mut macrophages 2 hours after plating on a fibronectin-coated surface (WT values for each experiment set to 1; n = 6 experiments; cells from 2 mice of each genotype). Values are given as means ± 95% confidence intervals. *P < .05.