Binding of K562 cells transfected with hLAIR-1a mutants to various collagens. (A) Flow cytometric analysis of LAIR-1 expression (y-axis) and FITC-conjugated collagen I binding (x-axis) on parent K562 cells (upper left panel) or K562 cells expressing wt or mutant LAIR-1a as indicated. Representative dot plots of at least 3 independent experiments are shown. Percentage of LAIR-1⁺ collagen-binding cells is indicated. (B) Summary flow cytometric analyses showing binding of soluble collagens I, III, and IV to parent K562 cells (−) and K562 cells expressing wt LAIR-1a or mutants as indicated. (C) Adhesion of parent K562 cells (−) and K562 cells expressing wt LAIR-1a or mutants as indicated to plate-bound collagens I, III, and IV. White bars indicate collagen I; black bars, collagen III; and striped bars, collagen IV (nt indicates not tested). Data represent mean ± SD of at least 3 independent experiments.