The intracellular tyrosine residues of the ATP-gated P2X(1) ion channel are essential for its function.
The four highly conserved intracellular tyrosine residues of the P2X(1) ion channel were mutated into phenylalanine. Simultaneous electrophysiological and calcium measurements in transfected human embryonic kidney (HEK 293) cells indicated that Y362F and Y370F mutants were non-functional, despite their proper plasma membrane expression. The Y16F and Y363F mutants retained 2.2% and 26% of the wild-type P2X(1) activity, respectively. However, no tyrosine phosphorylation was detected on Western blots of P2X(1) immunoprecipitates derived either from HEK 293 cell lysates or from human platelets, expressing P2X(1) endogenously. Thus, Y16, Y362, Y363 and Y370 are required for the appropriate three-dimensional structure and function of the intracellular P2X(1) domains.
Center for Molecular and Vascular Biology, University of Leuven, Herestraat 49, 3000 Leuven, Belgium.
Emese
E
Toth-Zsamboki
Cecile
C
Oury
Hiroyuki
H
Watanabe
Bernd
B
Nilius
Jos
J
Vermylen
Marc F
MF
Hoylaerts
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D006801:Humans; D015640:Ion Channel Gating; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D018048:Receptors, Purinergic P2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D058469:Receptors, Purinergic P2X; D017386:Sequence Homology, Amino Acid; D014443:Tyrosine / Q000378:metabolism*
D017931:DNA Primers; D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X; D014443:Tyrosine; D000255:Adenosine Triphosphate