The Transient Receptor Potential Channels TRPP2 and TRPC1 Form a Heterotetramer with a 2:2 Stoichiometry and an Alternating Subunit Arrangement

• Published in: The Journal of biological chemistry 2009-12, Vol.284 (51), p.35507-35513
• Main Authors: Kobori, Toshiro, Smith, Graham D., Sandford, Richard, Edwardson, J.Michael
• Format: Article
• Language: English
• Subjects: Cell Line; Humans; Microscopy, Atomic Force - methods; Molecular Basis of Cell and Developmental Biology; Multiprotein Complexes - chemistry; Multiprotein Complexes - genetics; Multiprotein Complexes - metabolism; Multiprotein Complexes - ultrastructure; Protein Structure, Quaternary - physiology; TRPC Cation Channels - chemistry; TRPC Cation Channels - genetics; TRPC Cation Channels - metabolism; TRPP Cation Channels - chemistry; TRPP Cation Channels - genetics; TRPP Cation Channels - metabolism; TRPV Cation Channels - chemistry; TRPV Cation Channels - genetics; TRPV Cation Channels - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M109.060228

There is functional evidence that polycystin-2 (TRPP2) interacts with other members of the transient receptor potential family, including TRPC1 and TRPV4. Here we have used atomic force microscopy to study the structure of the TRPP2 homomer and the interaction between TRPP2 and TRPC1. The molecular volumes of both Myc-tagged TRPP2 and V5-tagged TRPC1 isolated from singly transfected tsA 201 cells indicated that they assembled as homotetramers. The molecular volume of the protein isolated from cells expressing both TRPP2 and TRPC1 was intermediate between the volumes of the two homomers, suggesting that a heteromer was being formed. The distribution of angles between pairs of anti-Myc antibodies bound to TRPP2 particles had a large peak close to 90° and a smaller peak close to 180°, consistent with the assembly of TRPP2 as a homotetramer. In contrast, the corresponding angle distributions for decoration of the TRPP2-TRPC1 heteromer by either anti-Myc or anti-V5 antibodies had predominant peaks close to 180°. This decoration pattern indicates a TRPP2:TRPC1 subunit stoichiometry of 2:2 and an alternating subunit arrangement.