Atomic Force Microscopy Reveals the Alternating Subunit Arrangement of the TRPP2-TRPV4 Heterotetramer

作者：Stewart Andrew P; Smith Graham D; Sandford Richard N; Edwardson J Michael^*

来源：Biophysical Journal, 2010, 99(3): 790-797.

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 (TAP) 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 TAP channels.

• 出版日期2010-8-4
• 单位河北医科大学