Identification of the structural motif responsible for trimeric assembly of the C-terminal regulatory domains of polycystin channels PKD2L1 and PKD2

Molland, Katrina L.; Narayanan, A.; Burgner, John W.; Yernool, Dinesh

doi:10.1042/bj20091843

Cited by 17 publications

(18 citation statements)

References 59 publications

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“…We aligned TRPP2 and TRPP3 C-termini and found a putative coiled-coil domain in TRPP3 (Fig. 5a, b; also see 33 ). All hydrophobic amino acids important for the TRPP2 coiled-coil interaction 29 are conserved in TRPP3 (Fig.…”

Section: Resultsmentioning

confidence: 97%

Molecular mechanism of the assembly of an acid-sensing receptor ion channel complex

Ulbrich

et al. 2012

Nat Commun

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Polycystic kidney disease (PKD) family proteins associate with transient receptor potential (TRP) channel family proteins to form functionally important complexes. PKD proteins differ from known ion channel-forming proteins and are generally thought to act as membrane receptors. Here we find that PKD1L3, a PKD protein, functions as a channel-forming subunit in an acid-sensing heteromeric complex formed by PKD1L3 and TRPP3, a TRP channel protein. Single amino acid mutations in the putative pore region of both proteins alter the channel's ion selectivity. The PKD1L3/TRPP3 complex in the plasma membrane of live cells contains one PKD1L3 and three TRPP3. A TRPP3 C-terminal coiled-coil domain forms a trimer in solution and in crystal and plays a crucial role in the assembly and surface expression of the PKD1L3/TRPP3 complex. These results demonstrate that PKD subunits constitute a new class of channel-forming proteins, enriching our understanding of the function of PKD proteins and PKD/TRPP complexes.

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Section: Resultsmentioning

confidence: 97%

Molecular mechanism of the assembly of an acid-sensing receptor ion channel complex

Ulbrich

et al. 2012

Nat Commun

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“…In a previous study, we showed, by using static light scattering and X-ray crystallography, that the TRPP2 coiled-coil domain itself and four different TRPP2 C-terminal fragments containing the coiled-coil domain all form homomeric trimers, and that these trimers associate with a single PKD1 coiled-coil to form a 3∶1 complex (27). Two recent studies using a variety of biochemical and biophysical approaches also reported that the TRPP2 C terminus forms a trimer (28,29). On the other hand, another recent study reported that the TRPP2 C terminus forms a dimer (46).…”

Section: Discussionmentioning

confidence: 99%

“…This association involves coiled-coil domains in the C termini of the two proteins (25,27). The TRPP2 coiled-coil domain forms a homotrimer, both in solution (27)(28)(29) and in crystals (27). Disruption of this trimer abolishes the assembly of heteromeric TRPP2/PKD1 complexes (27).…”

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confidence: 99%

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

Zhu

Ulbrich

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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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.

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“…It has been found that both TRPP2 and PKD1 have intracellular C-terminal coiled-coil domains, which are involved in the association between TRPP2 and PKD1 (26,27). Further evidence showed that the coiled-coil domains from three TRPP2 subunits form a tightly bundled trimer in both solution and protein crystal (28,29). The downstream region of this trimer forms the PKD1-binding site and binds to one copy of the C-terminal coiled-coil domain of PKD1, determining a 3:1 (TRPP2/PKD1) subunit stoichiometry of the full-length complex (29,30).…”

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confidence: 97%

Extracellular Loops Are Essential for the Assembly and Function of Polycystin Receptor-Ion Channel Complexes

Salehi-Najafabadi¹,

Li²,

Valentino

et al. 2017

Journal of Biological Chemistry

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Edited by Norma AllewellPolycystin complexes, or TRPP-PKD complexes, made of transient receptor potential channel polycystin (TRPP) and polycystic kidney disease (PKD) proteins, play key roles in coupling extracellular stimuli with intracellular Ca 2؉ signals. For example, the TRPP2-PKD1 complex has a crucial function in renal physiology, with mutations in either protein causing autosomal dominant polycystic kidney disease. In contrast, the TRPP3-PKD1L3 complex responds to low pH and was proposed to be a sour taste receptor candidate. It has been shown previously that the protein partners interact via association of the C-terminal or transmembrane segments, with consequences for the assembly, surface expression, and function of the polycystin complexes. However, the roles of extracellular components, especially the loops that connect the transmembrane segments, in the assembly and function of the polycystin complex are largely unknown. Here, with an immunoprecipitation method, we found that extracellular loops between the first and second transmembrane segments of TRPP2 and TRPP3 associate with the extracellular loops between the sixth and seventh transmembrane segments of PKD1 and PKD1L3, respectively. Immunofluorescence and electrophysiology data further confirm that the associations between these loops are essential for the trafficking and function of the complexes. Interestingly, most of the extracellular loops are also found to be involved in homomeric assembly. Furthermore, autosomal dominant polycystic kidney disease-associated TRPP2 mutant T448K significantly weakened TRPP2 homomeric assembly but had no obvious effect on TRPP2-PKD1 heteromeric assembly. Our results demonstrate a crucial role of these functionally underexplored extracellular loops in the assembly and function of the polycystin complexes.

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Identification of the structural motif responsible for trimeric assembly of the C-terminal regulatory domains of polycystin channels PKD2L1 and PKD2

Cited by 17 publications

References 59 publications

Molecular mechanism of the assembly of an acid-sensing receptor ion channel complex

Molecular mechanism of the assembly of an acid-sensing receptor ion channel complex

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

Extracellular Loops Are Essential for the Assembly and Function of Polycystin Receptor-Ion Channel Complexes

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