S2 Cell-Adhesion Assay.

Drosophila S2 cells (Life Technologies) were transfected for 24 h as described in SI Appendix, and 1.5 × 10⁶ cells from each condition were mixed together at a density of 3 × 10⁶ cells per well (1 × 10⁶ cells/mL) and shaken gently at 28 °C for up to 2 h to allow aggregation. Cells were imaged immediately after the conditions were set up (t = 0) and after 30 min, 1 h, and 2 h. For full details, see SI Appendix.