title: Tyrosine phosphatase PTP1B interacts with TRPV6 in vivo and plays a role in TRPV6-mediated calcium influx in HEK293 cells.
abstract: This study investigates the role of tyrosine phosphorylation and dephosphorylation in the regulation of the Ca(2+) permeant TRPV6 channel. HEK293 cells co-transfected with TRPV6 and the tyrosine phosphatase PTP1B show a constitutive Ca(2+) entry which was independent of tyrosine phosphorylation under resting conditions. Following depletion of intracellular Ca(2+) stores, TRPV6-mediated Ca(2+) entry could be increased in the presence of a tyrosine phosphatase inhibitor (bis-(N,N-dimethyl-hydroxamido) hydroxo-vanadate; DMHV). Inhibition of Src-kinases completely abolished DMHV-induced increase in TRPV6-mediated Ca(2+) influx. Co-transfection with Src led to tyrosine phosphorylation of TRPV6 which could be dephosphorylated by PTP1B. In vivo interaction of TRPV6 with PTP1B was visualized using the bimolecular fluorescence complementation (BiFC) method and proved by co-immunoprecipitation of both proteins. These data indicate that tyrosine phosphorylation is involved in the regulation of the TRPV6 channel protein.
authors.affiliation: Physiological Institute, University of the Saarland, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Sternfeld
authors.forename: Elmar
authors.initials: E
authors.lastname: Krause
authors.forename: Andreas
authors.initials: A
authors.lastname: Schmid
authors.forename: Ines
authors.initials: I
authors.lastname: Anderie
authors.forename: Anna
authors.initials: A
authors.lastname: Latas
authors.forename: Hajaj
authors.initials: H
authors.lastname: Al-Shaldi
authors.forename: Andreas
authors.initials: A
authors.lastname: Köhl
authors.forename: Katrin
authors.initials: K
authors.lastname: Evers
authors.forename: Hans Werner
authors.initials: HW
authors.lastname: Hofer
authors.forename: Irene
authors.initials: I
authors.lastname: Schulz
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D002460:Cell Line; D003001:Cloning, Molecular; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D018715:Microscopy, Video; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000502:physiology*; D051381:Rats; D013050:Spectrometry, Fluorescence; D050916:TRPV Cation Channels; D013997:Time Factors; D014162:Transfection; D014443:Tyrosine / Q000737:chemistry / Q000378:metabolism; D014638:Vanadates / Q000494:pharmacology; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D050916:TRPV Cation Channels; C120776:TRPV6 channel; C402001:bis(N,N-dimethylhydroxamido)hydroxooxovanadate; D049452:Green Fluorescent Proteins; D014638:Vanadates; D014443:Tyrosine; D019061:src-Family Kinases; C516607:PTPN1 protein, human; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; C516610:Ptpn1 protein, rat; D002118:Calcium