Cell-type specific effects of endocytosis inhibitors on 5-hydroxytryptamine2A receptor desensitization and resensitization reveal an arrestin-, GRK2-, and GRK5-independent mode of regulation in human embryonic kidney 293 cells

John Gray, Douglas J. Sheffler, Anushree Bhatnagar, Jason A. Woods, Sandra J. Hufeisen, Jeffrey L. Benovic, Bryan L. Roth

Research output: Contribution to journalArticle

77 Scopus citations

Abstract

The effect of endocytosis inhibitors on 5-hydroxytryptamine2A (5-HT2A) receptor desensitization and resensitization was examined in transiently transfected human embryonic kidney (HEK) 293 cells and in C6 glioma cells that endogenously express 5-HT2A receptors. In HEK-293 cells, 5-HT2A receptor desensitization was unaffected by cotransfection with a dominant-negative mutant of dynamin (DynK44A), a truncation mutant of arrestin-2 [Arr2(319-418)], or by two well-characterized chemical inhibitors of endocytosis: concanavalin A (conA) and phenylarsine oxide (PAO). In contrast, β2-adrenergic receptor desensitization was significantly potentiated by each of these treatments in HEK-293 cells. In C6 glioma cells, however, DynK44A, Arr2(319- 418), conA, and PAO each resulted in the potentiation of 5-HT2A and β-adrenergic receptor desensitization. The cell-type-specific effect of Arr2(319-418) on 5-HT2A receptor desensitization was not related to the level of GRK2 or GRK5 expression. Interestingly, although β2-adrenergic receptor resensitization was potently blocked by cotransfection with DynK44A, 5-HT2A receptor resensitization was enhanced, suggesting the existence of a novel cell-surface mechanism for 5-HT2A receptor resensitization in HEK-293 cells. In addition, Arr2(319-418) had no effect on 5-HT2A receptor resensitization in HEK-293 cells, although it attenuated the resensitization of the β2-adrenergic receptor. However, in C6 glioma cells, both DynK44A and Arr2(319-418) significantly reduced 5-HT2A receptor resensitization. Taken together, these results provide the first convincing evidence of cell-type-specific roles for endocytosis inhibitors in regulating GPCR activity. Additionally, these results imply that novel GRK and arrestin-independent mechanisms of 5-HT2A receptor desensitization and resensitization exist in HEK-293 cells.

Original languageEnglish (US)
Pages (from-to)1020-1030
Number of pages11
JournalMolecular Pharmacology
Volume60
Issue number5
StatePublished - 2001
Externally publishedYes

    Fingerprint

ASJC Scopus subject areas

  • Pharmacology

Cite this