title: [Protein tyrosine phosphatase non-receptor type 12 negatively regulates cardiac HERG channel currents].
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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Cardiology, Guangdong Provincial Cardiovascular Institute, Guangdong General Hospital, Guangzhou 510080, China. E-mail: doctorlinjijin@163.com.
authors.forename: Jijin
authors.initials: J
authors.lastname: Lin
authors.forename: Shukai
authors.initials: S
authors.lastname: Liu
authors.forename: Fangfang
authors.initials: F
authors.lastname: Zheng
authors.forename: Qingyan
authors.initials: Q
authors.lastname: Ma
authors.forename: Hong
authors.initials: H
authors.lastname: Yu
authors.forename: Li
authors.initials: L
authors.lastname: Ren
authors.forename: Xinyuan
authors.initials: X
authors.lastname: Shen
mesh_terms: D051638:Ether-A-Go-Go Potassium Channels / Q000502:physiology*; D057809:HEK293 Cells; D006321:Heart; D006801:Humans; D008133:Long QT Syndrome; D018408:Patch-Clamp Techniques; D054594:Protein Tyrosine Phosphatase, Non-Receptor Type 12 / Q000502:physiology*; D014162:Transfection
chemical_list: D051638:Ether-A-Go-Go Potassium Channels; C516738:PTPN12 protein, human; D054594:Protein Tyrosine Phosphatase, Non-Receptor Type 12