Exclusion of a transmembrane phosphatase at the ligated membrane–membrane interface. (A) S2 transmembrane phosphatase expression data and schematic of Ptp69D-GFP domain structure highlighting features of its bulky extracellular domain. Phosphatase expression levels are indicated in reads per kilobase of transcript, per million mapped reads (RPKM). FN, fibronectin. (B) The transmembrane phosphatase Ptp69D segregates away from Draper at synapses between 10% PS beads and the S2 cell. Draper-mCherry and Ptp69D-GFP were cotransfected into S2 cells and localization at the synapse with 10% PS beads assessed after a 15-min incubation. Ptp69D-GFP was excluded from 22 of 24 synapses examined. (C) Draper-mCherry clusters exclude Ptp69D-GFP on 10% PS SLBs. Draper-mCherry/Ptp69D-GFP–expressing S2 cells were allowed to settle and spread on bilayers and localization of receptor and phosphatase assessed after 15 min. Ptp69D-GFP exclusion from Draper-mCherry was observed in 22 of 25 spread cells examined. Bars, 5 µm.