A natural dominant negative P2X1 receptor due to deletion of a single amino acid residue.
The P2X1 receptor belongs to a family of oligomeric ATP-gated ion channels with intracellular N and C termini and two transmembrane segments separating a large extracellular domain. Here, we describe a naturally occurring dominant negative P2X1 mutant. This mutant lacks one leucine within a stretch of four leucine residues in its second transmembrane domain (TM2) (amino acids 351-354). Confocal microscopy revealed proper plasma membrane localization of the mutant in stably transfected HEK293 cells. Nevertheless, voltage-clamped HEK293 cells expressing mutated P2X1 channels failed to develop an ATP or ADP-induced current. Furthermore, when co-expressed with the wild type receptor in Xenopus oocytes, the mutated protein exhibited a dose-dependent dominant negative effect on the normal ATP or ADP-induced P2X1 channel activity. These data indicate that deletion of a single apolar amino acid residue at the inner border of the P2X1 TM2 generates a nonfunctional channel. The inactive and dominant negative form of the P2X1 receptor may constitute a new tool for the study of the physiological role of this channel in native cells.
Oury
C
C
Center for Molecular and Vascular Biology and Laboratory of Physiology, University of Leuven, B-3000 Leuven, Belgium.
Toth-Zsamboki
E
E
Van Geet
C
C
Thys
C
C
Wei
L
L
Nilius
B
B
Vermylen
J
J
Hoylaerts
M F
MF
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry*; D001483:Base Sequence; D001778:Blood Coagulation Disorders / Q000235:genetics; D002460:Cell Line; D002648:Child; D017931:DNA Primers; D005260:Female; D005799:Genes, Dominant; D006801:Humans; D008969:Molecular Sequence Data; D018048:Receptors, Purinergic P2 / Q000737:chemistry / Q000235:genetics*; D058469:Receptors, Purinergic P2X; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid
D000596:Amino Acids; D017931:DNA Primers; D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X