FRTL-5 Rat Thyroid Cells Release Thyroglobulin Sequestered in Exosomes: A Possible Novel Mechanism for Thyroglobulin Processing in the Thyroid

Figure 5

SDS-PAGE and Tg Western blot of samples from different stages of exosome isolation by ultracentrifugation: 17,000 ×g pellet and supernatant, 200,000 ×g supernatant, and 200,000 ×g (exosome pellet) from samples of 5H medium (lanes 1, 5, 8, and 11), 6H medium (lanes 2, 6, 9, and 12), and 5H medium with 1 mg/mL Tg (lanes 3, 7, 10, and 13) from confluent cultures of FRTL-5 cells incubated for 48 hours. Additionally, lane 4 contains a sample of the 200,000 ×g pellet obtained from fresh 5H media (i.e., unexposed to FRTL-5 cells). Western blots were treated with a monoclonal anti-human-Tg antibody and developed using SuperSignal West Pico. “Exosome pellets” = 200,000 ×g pellets.