Cloning and pharmacological characterization of a fourth P2X receptor subtype widely expressed in brain and peripheral tissues including various endocrine tissues.
We have isolated cDNA encoding a fourth member (P2X-4) of the ATP receptor P2X receptor family from a rat pancreatic islet cDNA library. Rat P2X-4 is a protein of 388 amino acids which shares 50%, 49%, and 47% identity with P2X-1, P2X-2, and P2X-3, respectively, and has two putative transmembrane segments. Rat P2X-4 mRNA is widely expressed in brain and peripheral tissues, including various endocrine tissues, and it is also expressed in various hormone-secreting cell lines. We have heterologously expressed the cloned P2X-4 in Xenopus laevis oocytes and have characterized its pharmacological properties. ATP, its analogs and ADP activate cation-selective ion channels. The order of agonist potency is ATP ADP 2-methyl- thioATP(2MeSATP) >> alpha beta-methelene-ATP (alpha betameATP). ATP-evoked currents are only partially blocked by suramin, reactive blue-2, or H2DIDS. The present study suggests that P2X-4, with pharmacological properties distinct from those of P2X-1+, P2X-2, and P2X-3, mediates extracellular ATP-induced biological effects in non-neuronal cells, including endocrine cells, as well as in neuronal cells.
Wang
C Z
CZ
Center for Biomedical Science, Chiba University School of Medicine,   Inohana, Chuo-ku, Japan.
Namba
N
N
Gonoi
T
T
Inagaki
N
N
Seino
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004702:Endocrine Glands / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D066298:In Vitro Techniques; D008297:Male; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014982:Xenopus laevis
D018076:DNA, Complementary; D018048:Receptors, Purinergic P2; D011994:Recombinant Proteins