beta sub2 -Adrenergic receptor internalization, endosomal sorting and plasma membrane recycling are regulated by Rab GTPases

Reprogramming of G protein-coupled receptor recycling and signaling by a kinase switch

“…1A). On addition of the B2AR agonist isoproterenol (iso), receptors were rapidly internalized and redistributed to internal spherical membranes that have been characterized as early endosomes (10,15,16,21). Within these membranes, B2AR was concentrated in tubular domains (Fig.…”

“…Interestingly, the recycling of signaling receptors is functionally distinct from the recycling of constitutively cycling proteins like the transferrin receptor (TfR) (1,6,10,11). TfR recycles by "bulk" geometric sorting, largely independent of specific cytoplasmic sequences (12,13).…”

“…Recent work has identified physically and biochemically distinct microdomains on early endosomes that mediate B2AR recycling independent of TfR (14)(15)(16). Although the exact mechanisms of B2AR sorting into these domains remain under investigation, this sorting clearly requires specific sequence elements on B2AR (1,10,11,17). Importantly, why signaling receptor sorting is subject to such specialized requirements, considering that cargo like TfR apparently can recycle without specific sequence requirements, is not clear (1,(12)(13)(14)(15)(16).…”

Dispatched mediates Hedgehog basolateral release to form the long-range morphogenetic gradient in the Drosophila wing disk epithelium

“…S2 B and B′, arrowheads), where the recycling endosome compartment is probably located (38). Vertebrate Rab4 directs rapid recycling from early endosomes to the plasma membrane (39,40). We also observed a slight buildup of Hh protein in the apical part of the epithelium when we overexpressed a dominant-negative form of Rab4 ( Based on the above, we propose that in producing cells, the apical "secreted" Hh undergoes a subsequent endocytic internalization mediated by dynamin and Rab5 that leads to its "recycling" to the basolateral domain of the plasma membrane, where we believe the long-range Hh gradient is formed and shaped.…”

Regulation of G protein-coupled receptor trafficking and signaling by Rab GTPases

“…1,4 endosomal compartment. 21 Although dephosphorylation of cAMP-dependent protein kinase phosphorylated β 2 AR does not require endocytosis, 22 it remains unknown whether the dephosphorylation of PKC phosphorylated mGluR1a either occurs at the cell surface or requires endocytosis to endosomes. Thus, we hypothesize that mGluR1a dephosphorylation does not occur at the cell surface, and Rab8-dependent cell surface mGluR1a retention prevents the dephosphorylation of PKC phosphorylated mGluR1a in the endosomal compartment.…”