title: Phosphoinositide interacting regulator of TRP (Pirt) enhances TRPM8 channel activity in vitro via increasing channel conductance.
abstract: OBJECTIVE
  Pirt is a two-transmembrane domain protein that regulates the function of a variety of ion channels. Our previous study indicated that Pirt acts as a positive endogenous regulator of the TRPM8 channel. The aim of this study was to investigate the mechanism underlying the regulation of TRPM8 channel by Pirt.
  
  
  METHODS
  HEK293 cells were transfected with TRPM8+Pirt or TRPM8 alone. Menthol (1 mmol/L) was applied through perfusion to induce TRPM8-mediated voltage-dependent currents, which were recorded using a whole-cell recording technique. PIP2 (10 μmol/L) was added into the electrode pipettes (PI was taken as a control). Additionally, cell-attached single-channel recordings were conducted in CHO cells transfected with TRPM8+Pirt or TRPM8 alone, and menthol (1 mmol/L) was added into the pipette solution.
  
  
  RESULTS
  Either co-transfection with Pirt or intracellular application of PIP2 (but not PI) significantly enhanced menthol-induced TRPM8 currents. Furthermore, Pirt and PIP2 synergistically modulated menthol-induced TRPM8 currents. Single-channel recordings revealed that co-transfection with Pirt significantly increased the single channel conductance.
  
  
  CONCLUSIONS
  Pirt and PIP2 synergistically enhance TRPM8 channel activity, and Pirt regulates TRPM8 channel activity by increasing the single channel conductance.
authors.affiliation: College of Biology and Environmental Sciences, Jishou University, Jishou 416000, China.|College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
authors.forename: Min
authors.initials: M
authors.lastname: Tang
authors.affiliation: College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
authors.forename: Guang-yi
authors.initials: GY
authors.lastname: Wu
authors.affiliation: Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Xin-zhong
authors.initials: XZ
authors.lastname: Dong
authors.affiliation: College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
authors.forename: Zong-xiang
authors.initials: ZX
authors.lastname: Tang
mesh_terms: D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D015640:Ion Channel Gating; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008610:Menthol / Q000494:pharmacology; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000494:pharmacology; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; C529003:Pirt protein, mouse; D050053:TRPM Cation Channels; C425966:TRPM8 protein, human; D008610:Menthol