Structural and molecular basis of the assembly of the TRPP2/PKD1 complex.
Mutations in PKD1 and TRPP2 account for nearly all cases of autosomal dominant polycystic kidney disease (ADPKD). These 2 proteins form a receptor/ion channel complex on the cell surface. Using a combination of biochemistry, crystallography, and a single-molecule method to determine the subunit composition of proteins in the plasma membrane of live cells, we find that this complex contains 3 TRPP2 and 1 PKD1. A newly identified coiled-coil domain in the C terminus of TRPP2 is critical for the formation of this complex. This coiled-coil domain forms a homotrimer, in both solution and crystal structure, and binds to a single coiled-coil domain in the C terminus of PKD1. Mutations that disrupt the TRPP2 coiled-coil domain trimer abolish the assembly of both the full-length TRPP2 trimer and the TRPP2/PKD1 complex and diminish the surface expression of both proteins. These results have significant implications for the assembly, regulation, and function of the TRPP2/PKD1 complex and the pathogenic mechanism of some ADPKD-producing mutations.
Yu
Yong
Y
Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
Ulbrich
Maximilian H
MH
Li
Ming-Hui
MH
Buraei
Zafir
Z
Chen
Xing-Zhen
XZ
Ong
Albert C M
AC
Tong
Liang
L
Isacoff
Ehud Y
EY
Yang
Jian
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003460:Crystallization; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017422:Sequence Analysis, DNA; D050396:TRPP Cation Channels / Q000235:genetics* / Q000378:metabolism; D014981:Xenopus
D046912:Multiprotein Complexes; D050396:TRPP Cation Channels