Localization of receptors in discrete cellular microdomains undoubtedly contributes to their interaction with particular effectors and receptor targets. For G protein-coupled receptors, virtually nothing is known about the mechanisms and structural features responsible for their targeting to and retention in varying surface domains. We have shown that the Gj/Go-coupled α2A-adrenergic receptor (α2AAR) is directly targeted to the lateral subdomain of MDCK II cells. Mutational analysis has revealed that regions in or near the bilayer are likely critical for α2AAR targeting, whereas endofacial domains contribute to α2AAR retention on the lateral surface. Although the α2BAR also is enriched on the lateral subdomain at steady-state, its polarization occurs after initial random delivery to both apical and basolateral surfaces followed by a selective accumulation on the lateral subdomain. The α2CAR also is expressed on the lateral subdomain and achieves its localization via direct delivery to the basolateral surface; however, the α2CAR also exists in an as yet not fully characterized intracellular compartment. Interestingly, another Gj/Go-coupled receptor, the A1 adenosine receptor, is enriched on the apical surface of MDCK II calls and achieves this localization by direct apical delivery. These findings indicate that receptor delivery to polarized surfaces is not determined by receptor coupling to a specific subpopulation of G proteins.
|Original language||English (US)|
|Number of pages||11|
|Journal||Journal of Receptor and Signal Transduction Research|
|State||Published - Jan 1 1997|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology