Figure 3.

Importance of the TRH receptor carboxyl terminus. Wildtype TRH receptors or receptors deleted at amino acid 334 were incubated with TRH and IP3 mass was measured at intervals (graphs). To visualize arrestin, receptors were expressed with GFP-labeled arrestin3. To visualize receptors, cells were incubated with rhodamine-labeled TRH. GFP-arrestin is recruited to full-length TRH receptors and co-internalizes with them but it does not interact with truncated receptors, which do not internalize.