Structural model of the TRPP2/PKD1 C-terminal coiled-coil complex produced by a combined computational and experimental approach

Abstract

Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in TRPP2 and PKD1, which form an ion channel/receptor complex containing three TRPP2 and one PKD1. A TRPP2 C-terminal coiled-coil trimer, critical for the assembly of this complex, associates with a single PKD1 C-terminal coiled-coil. Many ADPKD pathogenic mutations result in the abolishment of the TRPP2/PKD1 coiled-coil complex. To gain molecular and functional insights into this heterotetrameric complex, we computationally constructed a structural model by using a two-step docking strategy, based on a known crystal structure of the TRPP2 coiled-coil trimer. The model shows that this tetrameric complex has a novel di-trimer configuration: An upstream trimer made of three TRPP2 helices and a downstream trimer made of two TRPP2 helices and one PKD1 helix. Mutagenesis and biochemical analysis identified critical TRPP2/ PKD1 interface contacts essential for the heteromeric coiled-coil complex. Mutation of these interface positions in the full-length proteins showed that these interactions were critical for the assembly of the full-length complex in cells. Our results provide a means to specifically weaken the TRPP2 and PKD1 association, thus facilitating future in vitro and in vivo studies on the functional importance of this association.

Polycystin-1 interacts with TAZ to stimulate osteoblastogenesis and inhibit adipogenesis

“…From this screen of compounds predicted to modulate protein:protein interactions, Zinc01442821 (4-phenyl-1H-pyrrole-3-carboxylic acid, designated MS for molecular staple) was the best compound predicted to bind to the α regions of PC2, as shown in Figure 7A. Figure 7B) (17).…”

“…We constructed a 3D model of the PC1:PC2 coiled-coil structure based on previous published structural information (17) and performed docking calculations (59, 60) to identify compounds …”

“…Zinc01442821 (4-phenyl-1H-pyrrole-3-carboxylic acid, C 11 H 9 NO 2 ) was identified by a computationally driven, structure-based, and virtual docking screening, following approaches previously described (59,60). Briefly, we used the PC1:PC2 coiled-coil model of Zhu et al (17) to perform a docking screening of 1,000 diverse fragment-like molecules from the ZINC database using the MOE docking facility (Chemical Computing Group) version 2015, in an induced-fit setting. Zinc01442821 ranks among the top molecules predicted to interact with residues in the binding pocket of PC2 in which PC1 binds.…”

“…PC1, an adhesion-like receptor (11,12), and PC2, a nonselective ion channel (13), interact through their respective coiled-coil domains to form a complex that senses fluid-shear stress in renal epithelial cells (14)(15)(16)(17). Inactivating mutations of either PKD1 or PKD2 cause renal cystic disease in mice (18,19) and autosomal dominant polycystic kidney disease (ADPKD) in humans (20,21).…”

The functions of TRPP2 in the vascular system

“…These new heteromultimeric channels typically have many novel biophysical properties, modes of activation, or simply more efficient trafficking of the ion conducting subunit to the plasma membrane [42] . To date, the literature has shown that the TRPP2 subunit might assemble into both homomeric and heteromeric complex channels with polycystin-1 [43,44] , TRPC1 [29,[45][46][47] , TRPC3 [48] , TRPC4 [49] , TRPC5 [50] , TRPC7 [48] and TRPV4 [51][52][53] . The pharmacology associated with TRPP2 is poorly understood.…”