Abstract
Plasma membrane (PM) expression of G-protein coupled receptors (GPCRs) is required for activation by extracellular ligands; however, mechanisms that regulate PM expression of GPCRs are poorly understood. For some GPCRs, such as alpha2c-adrenergic receptors (α2c-ARs), heterologous expression in non-native cells results in limited PM expression and extensive endoplasmic reticulum (ER) retention. Recently, ER export/retentions signals have been proposed to regulate cellular trafficking of several GPCRs. By utilizing a chimeric α2a/α2c-AR strategy, we identified an evolutionary conserved hydrophobic sequence (ALAAALAAAAA) in the extracellular amino terminal region that is responsible in part for α2c-AR subtype-specific trafficking. To our knowledge, this is the first luminal ER retention signal reported for a GPCR. Removal or disruption of the ER retention signal dramatically increased PM expression and decreased ER retention. Conversely, transplantation of this hydrophobic sequence into α2a-ARs reduced their PM expression and increased ER retention. This evolutionary conserved hydrophobic trafficking signal within α2c-ARs serves as a regulator of GPCR trafficking.
Original language | English |
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Pages (from-to) | 560-578 |
Number of pages | 19 |
Journal | Traffic |
Volume | 11 |
Issue number | 4 |
DOIs | |
Publication status | Published - Apr 2010 |
Externally published | Yes |
Keywords
- ER export
- ER retention
- GPCR trafficking
- Protein sorting
- Retention signal