摘要：Clustered protocadherins (Pcdhs), which are cell adhesion molecules, play a fundamental role in self-recognition and non-self-discrimination by conferring diversity on the cell surface. Although systematic cell-based aggregation assays provide information regarding the binding properties of Pcdhs, direct visualization of Pcdh
trans interactions across cells remains challenging. Here, we present Förster resonance energy transfer (FRET)-based indicators for directly visualizing Pcdh
trans interactions. We developed the indicators by individually inserting FRET donor and acceptor fluorescent proteins (FPs) into the ectodomain of Pcdh molecules. They enabled successful visualization of specific
trans interactions of Pcdh and revealed that the Pcdh
trans interaction is highly sensitive to changes in extracellular Ca
2+ levels. We expect that FRET-based indicators for visualizing Pcdh
trans interactions will provide a new approach for investigating the roles of Pcdh in self-recognition and non-self-discrimination processes.
