کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5816294 | 1116120 | 2016 | 6 صفحه PDF | دانلود رایگان |
BackgroundRecently is has been shown that α- and β-hederin increase the β2-adrenergic responsiveness of alveolar type II cells (A549) and human airway smooth muscle cells (HASM), respectively, by inhibiting the internalization of β2-adrenergic receptors (β2AR) under stimulating conditions. Internalization of β2AR is initiated by phosphorylations of certain serines and threonines by cAMP dependent protein kinase A (PKA) and G protein-coupled receptor kinases (GRK).PurposeTo evaluate the effect of α-hederin on PKA and GRK2 mediated phosphorylation of GFP-tagged β2AR.Study designTo study this process we performed In-Cell Western using isoprenaline stimulated HEK293 cells overexpressing β2AR as GFP fusion protein and specific antibodies against PKA (Ser345/346) and GRK2 (Ser355/356) phosphorylation sites.ResultsThere was no effect found on the PKA mediated phosphorylation (n = 14) but we could show that α-hederin (1 µM, 12 h) significantly inhibits GRK2 mediated phosphorylation at Ser355/356 by 11 ± 5% (n ⥠29, p ⤠0.01) under stimulating conditions compared to the positive control. In Förster resonance energy transfer (FRET) experiments using the isolated kinases in solution α-hederin did not show any influence neither to GRK2 nor to PKA.ConclusionTaken together, these results indicate that α-hederin acts as an indirect GRK2 inhibitor leading to a reduced homologous desensitization of β2AR-GFP in HEK293 cells
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Journal: Phytomedicine - Volume 23, Issue 1, 15 January 2016, Pages 52-57