HCMV-encoded chemokine receptor US28 employs multiple routes for internalization.
The human cytomegalovirus-encoded G protein-coupled receptor homologue US28 binds inflammatory chemokines and sequesters them from the environment of infected cells. Low surface deposition and endocytosis are dependent on constitutive C-terminal phosphorylation, suggesting a requirement for beta-arrestin binding in receptor internalization. In this report, a US28-dependent redistribution of beta-arrestin into vesicular structures occurred, although internalization of US28 was independent of beta-arrestin. Internalization of US28 was dynamin-dependent, and US28 partially partitioned into the detergent-resistant membrane fraction. Endocytosis was diminished by cholesterol depletion, yet sucrose inhibition was even stronger. The relevance of the clathrin-coated pit pathway was supported by colocalization of beta(2)-adaptin and US28 in endocytic compartments. Exchange of the C-terminal dileucine endocytosis motif inhibited rapid endocytosis, indicating a direct interaction of US28 with the AP-2 adaptor complex. We suggest that the arrestin-independent, dynamin-dependent internalization of US28 reveals a differential sorting of beta-arrestins and the virally encoded chemokine receptor homologue.
Department of Hematology, Oncology, and Tumor Immunology, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Jana
J
Droese
Thilo
T
Mokros
Ricardo
R
Hermosilla
Ralf
R
Schülein
Martin
M
Lipp
Uta E
UE
Höpken
Armin
A
Rehm
D019390:Arrestins / Q000378:metabolism*; D021941:Caveolae / Q000378:metabolism* / Q000648:ultrastructure; D002460:Cell Line; D034281:Dynamins / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology*; D006801:Humans; D007668:Kidney / Q000166:cytology* / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism / Q000648:ultrastructure; D016297:Mutagenesis, Site-Directed; D019707:Receptors, Chemokine / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014018:Tissue Distribution; D014764:Viral Proteins / Q000378:metabolism*; D000071557:beta-Arrestins
D019390:Arrestins; D019707:Receptors, Chemokine; D011994:Recombinant Proteins; C411191:US28 receptor, Cytomegalovirus; D014764:Viral Proteins; D000071557:beta-Arrestins; D034281:Dynamins