Atomic force microscopy reveals the alternating subunit arrangement of the TRPP2-TRPV4 heterotetramer

Biophys J. 2010 Aug 4;99(3):790-7. doi: 10.1016/j.bpj.2010.05.012.


There is evidence that polycystin-2 (TRPP2) interacts with two other members of the transient receptor potential (TRP) family, TRPC1 and TRPV4. We have previously shown that TRPP2 forms a heteromeric complex with TRPC1, with a 2:2 stoichiometry and an alternating subunit arrangement. Here, we used coimmunoprecipitation to show that TRPP2 also interacts with TRPV4, but not with TRPA1 or TRPM8; hence, its promiscuity is limited. We then used atomic force microscopy to study the structure of the TRPV4 homomer and the interaction between TRPP2 and TRPV4. The molecular volume of V5-tagged TRPV4 isolated from singly-transfected tsA 201 cells indicated that it assembled as a homotetramer. The distribution of angles between pairs of anti-V5 antibodies bound to TRPV4 particles had a large peak close to 90 degrees and a smaller peak close to 180 degrees , again consistent with the assembly of TRPV4 as a homotetramer. In contrast, the angle distributions for decoration of the TRPP2-TRPV4 heteromer by either anti-Myc or anti-V5 antibodies had major peaks close to 180 degrees. This result indicates that TRPP2-TRPV4 assembles identically to TRPP2-TRPC1, suggesting a common subunit arrangement among heteromeric TRP channels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Humans
  • Immunoprecipitation
  • Mice
  • Microscopy, Atomic Force*
  • Protein Multimerization*
  • Protein Subunits / metabolism*
  • Rats
  • TRPP Cation Channels / isolation & purification
  • TRPP Cation Channels / metabolism*
  • TRPV Cation Channels / isolation & purification
  • TRPV Cation Channels / metabolism*


  • Protein Subunits
  • TRPP Cation Channels
  • TRPV Cation Channels
  • Trpv4 protein, mouse
  • polycystic kidney disease 2 protein