Exosome secretion kinetics are controlled by tethering and temperature

Abstract

Multi-vesicular endosomes (MVEs) fuse with the plasma membrane to release exosomes into the extracellular space. The regulation and kinetics of this process is not well characterized, but probes for imaging MVE fusion have arisen recently. In particular, the design of an exosome marker with a pH sensitive dye in the middle of the tetraspanin protein CD63 has facilitated studies of individual MVE fusion events. Fusion events have been imaged using pHuji or pHluorin, while docking, protein accumulation during the fusion and docking process is imaged in another color channel using total internal reflection fluorescence microscopy.