Internalization of metabotropic glutamate receptor in C6 cells through clathrin-coated vesicles.
C6 glioma cells were treated for hours with 100 microM L-glutamate, quisqualate or trans-ACPD. In all cases, phospholipase C-coupled metabotropic glutamate receptors (mGluRs) present in these cells are down-regulated after this agonist treatment. Cell surface metabotropic glutamate receptor density was minimum at 6 h of agonist treatment and reached near control values after 30 h of treatment. This recovery was associated with a progressive increase in mGluR1 and mGluR1a mRNA level between 6 and 24 h and was not due to agonist removal. Specific L-[3H]glutamate or [3H](+/-)trans-ACPD binding decrease detected in C6 cells after 6 h of 100 microM L-glutamate treatment was associated with a remarkable increase of specific L-[3H]glutamate binding detected in clathrin-coated vesicles isolated from these treated cells. Moreover, this decrease was blocked in the presence of 0.5 M sucrose or 1 microM phenylarsine oxide, suggesting that desensitization and down-regulation of mGluR can be due to an endocytosis process through clathrin-coated pits and vesicles.
Luis Albasanz
José
J
Departamento de Química Inorgánica, Orgánica y Bioquímica, Facultad de Químicas, Universidad de Castilla-La Mancha, Avda Camilo José Cela, 10, 13071 Ciudad Real, Spain.
Fernandez
Mercedes
M
Martín
Mairena
M
D027322:Amino Acid Transport System X-AG / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D001152:Arsenicals / Q000494:pharmacology; D001665:Binding Sites / Q000187:drug effects / Q000502:physiology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D002490:Central Nervous System / Q000378:metabolism*; D022163:Clathrin-Coated Vesicles / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005910:Glioma; D018698:Glutamic Acid / Q000378:metabolism / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D018094:Receptors, Metabotropic Glutamate / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013395:Sucrose / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D014407:Tumor Cells, Cultured
D027322:Amino Acid Transport System X-AG; D001152:Arsenicals; D004791:Enzyme Inhibitors; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018094:Receptors, Metabotropic Glutamate; C029341:oxophenylarsine; D018698:Glutamic Acid; D013395:Sucrose