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OBJECTIVE To investigate the effect of root saponins of Panax notoginseng(RPNS) on different voltage-dependent calcium and potassium ion channels. METHODS By using the two-elec?trode voltage clamp (TEVC), the effect of RPNS 0.01, 0.06, 0.1, 0.6, 1 and 4 g · L- 1 was investigated on Cav1.2,and the effect of RPNS 1 g · L-1 was evaluated on Cav2.1,Cav2.2,Cav3.1, KCNH2,KCNQ1,KCNQ1/KCNE1 and BK channel. All the ion channels examined were expressed in Xenopus laevis oocytes. RESULTS TEVC suggested that the effect of RPNS on Cav1.2 exhibited the concentration-response relationship and its EC50 was 0.048 g · L-1. Compared with cell control,TEVC also showed that RPNS 1 g·L-1 had obviously inhibitory effect on Cav1.2,Cav2.2 and Cav3.1,and the inhibitory rate of RPNS 1 g · L-1 on the peak current of Cav1.2,Cav2.2 and Cav3.1 was(57.1 ± 8.6)%, (17.2 ± 0.7)% and(50.2 ± 7.7)%(P<0.01),respectively. RPNS 1 g · L-1 had obviously activated effect on BK channel,and the activated rate of RPNS 1 g·L-1 on the peak current of BK channel was(37.9± 2.7)%(P<0.01). RPNS 1 g·L-1 showed no significant effect on Cav2.1,KCNH2,KCNQ1 and KCNQ1/KCNE1. CONCLUSION RPNS may effectively inhibit Cav1.2 and Cav3.1,activate BK channel,but have little effect on Cav2.1,Cav2.2,KCNH2,KCNQ1 and KCNQ1/KCNE1.
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<p><b>OBJECTIVE</b>To screen the hepatocyte proteins that interact with hepatitis B virus X protein (HBx).</p><p><b>METHODS</b>The recombinant plasmid pSos-HBx was constructed by inserting Sos-HBx fragment into the bait vector, and after sequence verification the plasmid was transformed into competent yeast cells. The expression and self-activation of Sos-HBx protein was detected in the yeast cells. The hepatocyte proteins interacting with the bait protein was screened with CytoTrap yeast two-hybrid technique.</p><p><b>RESULTS</b>The reconstructed plasmid harboring HBx gene expressed Sos-HBx protein in the yeast cells without self-activation of the protein. CytoTrap yeast two-hybrid system identified 6 hepatocyte proteins that interacted with HBx, including fibronectin 1, translationally controlled tumor protein, IQ motif and WD repeats 1, follistatin, orosomucoid 1, and disulfide isomerase family A member 3.</p><p><b>CONCLUSION</b>Six HBx-binding hepatocyte proteins have been identified using the CytoTrap yeast two-hybrid system, which provides clues for further investigation of the role of HBx protein in hepatitis and liver cancer.</p>