Mechanistic study of β-tubulin and its interaction with the dopamine D5 receptor, cholecystokinin B receptor, and water-sodium metabolism / 中国比较医学杂志

ABSTRACT

Objective To examine the role of β-tubulin on the interaction between the cholecystokinin B receptor (CCKBR),dopamine D5 receptor(D5R), and water-sodium metabolism. Methods Normotensive and hypertensive renal proximal tubular cells(RPTC)were equally randomized into three separate groups a gastrin group, fenoldopam group,and gastrin+nocodazole group. Immunofluorescence was used to determine localization of β-tubulin,CCKBR,and D5R. Western blotting was used to detect CCKBR, D5R, and Na-K-ATP expression. Results Gastrin stimulation in normotensive RPTC increased D5R expression(P < 0.05)and decreased Na-K-ATP expression(P < 0.05). These changes were blocked by a tubulin inhibitor(P < 0.05). However, interaction between CCKBR, D5R, and Na-K-ATP expression was not significantly affected in hypertensive RPTC. Immunofluorescence showed that CCKBR and D5R can induce one another,followed by transport to the plasma membrane, which can prevented by a tubulin inhibitor. Further, tubulin is disordered in hypertensive RPTC,which cannot support intracellular CCKBR and D5R transport. Conclusions tubulin plays a key role in the interaction between CCKBR, D5R, and water-sodium metabolism by improving protein transfer from the cytoplasm to cell membrane.