Subcellular Trafficking of the TRH Receptor: Effect of Phosphorylation

摘要: Activation of the G protein-coupled TRH receptor leads to its phosphorylation and internalization. These studies addressed fundamental question whether regulates trafficking or endosomal localization state receptor. Trafficking phosphorylated dephosphorylated receptors was characterized using phosphosite-specific antibody after labeling surface with an extracellular epitope tag. Rab5 phosphoreceptor did not colocalize at plasma membrane immediately addition but overlapped extensively by 15 min. Dominant-negative Rab5-S34N inhibited Later, in endosomes containing Rab4. Dephosphorylated colocalized Rab4 Rab5. Rab4, -5, -11 affect dephosphorylation, showing that determines Rab4+/Rab5− vesicles vice versa. No Rab7; a small amount Rab11. To characterize recycling, were tagged antibody, N-terminal biotin ligase acceptor sequence labeled biotin. Most recycling return for more than 2 h removed, whereas total cell density largely restored less 1 h, indicating recruited contribute heavily early repopulation membrane.