title: Identification of tyrosines in the putative regulatory site of the Ca2+ channel TRPV6.
abstract: In HEK293 cells, transfected with the Ca2+ channel protein TRPV6, Ca2+ influx is increased and TRPV6 is tyrosine phosphorylated following addition of the tyrosine phosphatase inhibitor N,N-dimethyl-hydroxamido hydroxovanadate to cells. This effect of DMHV is enhanced by co-transfection of cells with the tyrosine kinase Src and the tyrosine phosphatase 1B. It is abolished when cells had been treated with PP1, an inhibitor of Src family tyrosine kinases. PTP1B interacts with the N-terminal domain of TRPV6 within a region of amino acids 1-191 as shown by co-immunoprecipitation, bimolecular fluorescence complementation and the yeast 2-hybrid system. Point mutation of both tyrosines 161 and 162 in the TRPV6 protein abolishes the DMHV-effect on Ca2+ influx and tyrosine phosphorylation by Src. Single mutations of Y161 or Y162 shows that each of both tyrosines alone is sufficient for the DMHV-effect. We conclude that phosphorylation/dephosphorylation of tyrosines in position 161 and 162 is essential for regulation of Ca2+ influx through TRPV6 Ca2+ channels in HEK293 cells.
authors.affiliation: Physiological Institute, University of Saarland, 66421 Homburg (Saar), Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Sternfeld
authors.forename: Ines
authors.initials: I
authors.lastname: Anderie
authors.forename: Andreas
authors.initials: A
authors.lastname: Schmid
authors.forename: Hajaj
authors.initials: H
authors.lastname: Al-Shaldi
authors.forename: Elmar
authors.initials: E
authors.lastname: Krause
authors.forename: Thomas
authors.initials: T
authors.lastname: Magg
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schreiner
authors.forename: Hans-Werner
authors.initials: HW
authors.lastname: Hofer
authors.forename: Irene
authors.initials: I
authors.lastname: Schulz
mesh_terms: D000595:Amino Acid Sequence; D015220:Calcium Channels / Q000737:chemistry* / Q000235:genetics; D002478:Cells, Cultured; D006801:Humans; D017354:Point Mutation; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D050916:TRPV Cation Channels / Q000737:chemistry* / Q000235:genetics; D014162:Transfection; D020798:Two-Hybrid System Techniques; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology; D019061:src-Family Kinases / Q000502:physiology
chemical_list: D015220:Calcium Channels; D050916:TRPV Cation Channels; C422827:TRPV6 protein, human; C402001:bis(N,N-dimethylhydroxamido)hydroxooxovanadate; D014638:Vanadates; D014443:Tyrosine; D019061:src-Family Kinases; D017027:Protein Tyrosine Phosphatases