Protein tyrosine phosphatase non-receptor type 12 negatively regulates cardiac HERG chan-nel currents
LIN Jijin
LIU Shukai
ZHENG Fangfang
MA Qingyan
YU Hong
REN Li
SHEN Xinyuan
Abstract：Objective To study the effect of protein tyrosine phosphatase non-receptor type 12 (PTPN12) in regulating cardiac HERG channel currents. Methods The plasmids pcDNA3.1-PTPN12-RFP and herg mutant constructed by PCR technique were transfected into HEK293 cells via Lipofectamine 2000, and the cells stably expressing PTPN12 selected with G418 were identified by Western blotting with anti-PTPN12 antibody. HERG channel current in cells expressing HERG alone (HEK293/HERG cells), cells overexpressing PTPN12 (HEK293/HERG cells transfected with pCDNA3.1-PTPN12-RFP), PAO-treated cells (PTPN12/HERG cells treated with PAO), and herg mutant cells (HEK293/HERGY327A-Y700A-Y845A cells transfected with pcDNA3.1-PTPN12-RFP) were recorded by patch-clamp technique. Results The plasmids pcDNA3.1-PTPN12-RFP and herg mutant were successfully constructed, and the stable expressing cell lines were established. Red fluorescence was obversed in HEK293/HERG cells transfected with pcDNA3.1- PTPN12- RFP, and the protein expression of PTPN12 was detected. Overexpression of PTPN12 significantly decreased HERG current density in HEK293/HERG cells, and this change was significantly weakened in the inhibitor group and herg mutant group. Conclusion PTPN12 negatively regulates cardiac HERG channel cerrent possibly by decreasing the phosphorylation level of HERG tyrosine residues. This finding provides further insight into the regulatory mechanism of HERG channel and the pathogenesis of long QT syndrome.
Keywords：long QT SyndromeHERG potassium channelprotein tyrosine phosphatase non-receptor type 12patch-clamp technique
Publication Date：2013-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 1718-1722 )