Use this URL to cite or link to this record in EThOS:
Title: Trafficking and assembly of P2X receptors
Author: Guo, C.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2007
Availability of Full Text:
Full text unavailable from EThOS.
Please contact the current institution’s library for further details.
Within the P2X family, P2X7 is claimed to be unique in not forming heteromers; however, we have used different approaches to demonstrate that P2X4 and P2X7 interact both structurally and functionally. First, when heterologously co-expressed, P2X7 was co-localized with P2X4 at the plasma membrane and co-expression with P2X7 increased the proportion of P2X4 at the cell surface, as measured by surface biotinylation. Second, in co-expressed cells, P2X7 was co-immunoprecipitated with an anti-HA antibody that recognized an HA-tagged form of P2X4. Similarly P2X4 was co-immunoprecipitated with an antibody to P2X7. Third, co-expression with a dominant-negative mutant of P2X4 (P2X4 C353W) with either wild type P2X4 or P2X7 reduced the amplitudes of currents, whereas co-expression of a non-functional but non-dominant-negative mutant (P2X4 S341W) potentiated currents. Neither mutant exhibited an obvious trafficking defect, nor did they alter the surface expression of P2X7 as measured by biotinylation. Finally we identified novel pharmacological properties of the heteromeric receptors. Similar to P2X7 receptors, they are 1) preferentially activated by 2’,3’-O-(benzoyl-4-benzoyl)-ATP (BzATP) and ATP4- as compared to MgATP, 2) the currents desensitize slowly, 3) the currents are sensitive to extracellular Na+ and 4) currents are blocked by Brilliant Blue G (BBG). However, unlike P2X7, the heteromeric receptor currents were potentiated by ivermectin (IVM) and inhibited by 2’,3’-O-(2,4,6-trinitrophenyl) adenosine 5-triphosphate (TNP-ATP). In a separate study, molecular determinants of P2X2 receptor trafficking demonstrated that the last few amino acids within the C-terminus, which are conserved in different spliced forms of P2X2 receptors, appear to be involved in the stabilization of P2X2 receptors at the plasma membrane.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available