کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9013085 1125059 2005 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Mrp2/Abcc2 transport activity is stimulated by protein kinase Cα in a baculo virus co-expression system
موضوعات مرتبط
علوم پزشکی و سلامت پزشکی و دندانپزشکی کاردیولوژی و پزشکی قلب و عروق
پیش نمایش صفحه اول مقاله
Mrp2/Abcc2 transport activity is stimulated by protein kinase Cα in a baculo virus co-expression system
چکیده انگلیسی
Cholestatic and choleretic effect are well known for protein kinase C activator and inhibitor, respectively. However, post-translational regulation, especially the effect of phosphorylation status of the biliary transporters on their intrinsic transport activity has not been fully understood. In this study, effect of phosphorylation on the transport activity of Mrp2, a biliary organic anion transporter, was examined in membrane vesicles isolated from Sf9 cells co-expressing excess amount of protein kinase Cα (PKCα). Mrp2-mediated transport activity was enhanced to three-fold by co-expressing PKCα. At the same time, phosphorylation of Mrp2 was also detected. The Km and Vmax values for the transport of [3H]estradiol-17β-D-glucuronide exhibited a 1.5-fold decrease and a 1.9-fold increase, respectively. Probenecid (100 μM) and benzylpenicillin (1 mM), both are activator of Mrp2, did not stimulated the transport activity of phosphorylated Mrp2. On the other hand, transport activity was further stimulated by Estron-3-sulfate and taurocholic acid. Similar mechanism that occurred in the presence of probenecid and benzylpenicillin, but different from that occurred in the presence of Estron-3-sulfate and taurocholic acid seems to be involved in the stimulation. Considering the discrepancy between the previous in vivo inhibitory effect of PKC activators and our in vitro stimulatory effect of PKCα on Mrp2 transport activity, direct modulation of Mrp2-transport activity may be minor if any under in vivo condition.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Life Sciences - Volume 77, Issue 5, 17 June 2005, Pages 539-550
نویسندگان
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