Abstract
P2X7 is an ATP-gated membrane ion channel that is expressed by multiple cell types. Brief exposure to ATP induces the opening of a nonselective cation channel; while repeated or prolonged exposure induces formation of a transmembrane pore. This process may be partially regulated by alternative splicing of full-length P2RX7A pre-mRNA, producing isoforms that delete or retain functional domains. Here, we report cloning and expression of a novel P2RX7 splice variant, P2RX7L, that is, characterized by skipping of exons 7 and 8. In HEK 293 cells, expression of P2RX7L produces a protein isoform, P2X7L, that forms a heteromer with P2X7A. A haplotype defined by six single nucleotide polymorphisms (SNPs) (rs208307, rs208306, rs36144485, rs208308, rs208309, and rs373655596) promotes allele-specific alternative splicing, increasing mRNA levels of P2RX7L and another isoform, P2RX7E, which in addition has a truncated C-terminus. Skipping of exons 7 and 8 is predicted to delete critical amino acids in the ATP-binding site. P2X7L-transfected HEK 293 cells have phagocytic but not channel, pore, or membrane-blebbing function, and double-transfected P2X7L and P2X7A cells have reduced pore function. Heteromeric receptor complexes of P2X7A and P2X7L are predicted to have reduced numbers of ATP-binding sites, which potentially alters receptor function compared to homomeric P2X7A complexes.
Original language | English |
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Pages (from-to) | 3884-3901 |
Number of pages | 18 |
Journal | The FASEB Journal |
Volume | 34 |
Issue number | 3 |
Early online date | 31 Jan 2020 |
DOIs | |
Publication status | Published - Mar 2020 |
Keywords
- P2X7
- alternative splicing
- heteromer
- single nucleotide polymorphism
- ALLELE
- CANCER-CELLS
- ACTIVATION
- C-TERMINUS
- QUANTITATIVE METHOD
- PORE FORMATION
- ATP-BINDING
- P2X(7) RECEPTOR
- P2X7 RECEPTOR
- ION-CHANNEL
Profiles
-
Leanne Stokes
- School of Chemistry, Pharmacy and Pharmacology - Associate Professor in Pharmacology
- Molecular and Tissue Pharmacology - Member
Person: Research Group Member, Academic, Teaching & Research