IL1β tethered to a supported lipid membrane forms clusters that recruit MyD88-GFP (related to Fig. 2). This video shows an EL4 cell expressing MyD88-GFP (middle, green channel in merge) interacting with a SLB functionalized with IL1β-JF646 (left, magenta channel in merge). The video illustrates that the IL1β clustering at the cell-supported membrane interface precedes the recruitment and formation of MyD88-GFP puncta at the cell surface. Same cell as shown in Fig. 2 C. Scale bar, 5 µm.