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. 2016 Feb;23(2):180-186.
doi: 10.1038/nsmb.3159. Epub 2016 Jan 18.

Cryo-electron microscopy structure of the TRPV2 ion channel

Lejla Zubcevic #  1 , Mark A Herzik Jr #  2 , Ben C Chung  1 , Zhirui Liu  1 , Gabriel C Lander  2 , Seok-Yong Lee  1
Affiliations

Cryo-electron microscopy structure of the TRPV2 ion channel

Lejla Zubcevic et al. Nat Struct Mol Biol. 2016 Feb.

Abstract

Transient receptor potential vanilloid (TRPV) cation channels are polymodal sensors involved in a variety of physiological processes. TRPV2, a member of the TRPV family, is regulated by temperature, by ligands, such as probenecid and cannabinoids, and by lipids. TRPV2 has been implicated in many biological functions, including somatosensation, osmosensation and innate immunity. Here we present the atomic model of rabbit TRPV2 in its putative desensitized state, as determined by cryo-EM at a nominal resolution of ∼4 Å. In the TRPV2 structure, the transmembrane segment 6 (S6), which is involved in gate opening, adopts a conformation different from the one observed in TRPV1. Structural comparisons of TRPV1 and TRPV2 indicate that a rotation of the ankyrin-repeat domain is coupled to pore opening via the TRP domain, and this pore opening can be modulated by rearrangements in the secondary structure of S6.

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Figures

Figure 1
Figure 1
3D reconstruction of rabbit TRPV2 and overall topology of the channel. (a) Cryo-EM reconstruction, showing the four-fold-symmetric TRPV2 homotetramer. Each promoter is colored differently. (b) The atomic model of TRPV2 built from the EM density, with the domain architecture delineated by different colors. (c) Linear diagram of the TRPV2 channel topology, with the domains colored as in b. (d) A view of the protomer subdomains. (e) Close-up view of the coupling domain (pre-S1 helix, linker domain and CTD) along with the TRP domain.
Figure 2
Figure 2
Pore structure of TRPV2. (a) Profile of the TRPV2 pore generated with HOLE software indicates two main constrictions: one at the selectivity filter formed by the side chains of Met605 and the backbone carbonyls of Gly604, and the second one close to the helix-bundle crossing, formed by the side chains of Met643. (b) Comparison of the pores of the closed TRPV1 and the TRPV2 channels, showing that the lower gate of TRPV1 is formed by Ile679, whereas the lower gate in TRPV2 is one turn lower, at Met643. (c) Comparison of the TRPV1 and TRPV2 S6 helices shows that the S6 helix in TRPV1 contains a π-helical segment, whereas the S6 in TRPV2 is α-helical.
Figure 3
Figure 3
Comparison of the pore-helix and pore-loop regions of TRPV1 and TRPV2. (a) Top view of the channel pore. The pore helix of TRPV2 (blue) and the closed TRPV1 channel (red) are in the same conformation, whereas the pore loop of TRPV2 adopts a conformation more similar to that of the open TRPV1 channel (green). Methionine residues of the selectivity filters of the closed and open TRPV1 (red and pink, respectively) and TRPV2 (blue) are shown in stick representation. (b) View of the coupling between the pore loop and turret in the closed TRPV1 structure (red), open TRPV1 structure (green) and TRPV2 structure (blue).
Figure 4
Figure 4
ARD twist and associated conformational changes in the coupling domain and the TRP domain. (a) Top view of the TRPV1 and TRPV2 channels. Overlay of the pore domains (gray) of the closed TRPV1, open TRPV1 and TRPV2 channels, indicating that the ARD of the open TRPV1 and TRPV2 have undergone a counterclockwise rotation relative to the closed TRPV1. (b) Close-up comparison of the pre-S1 helix, the linker and TRP domain of the open TRPV1 (green) with the closed TRPV1 (red) and with the TRPV2 channel (blue). TRPV1 undergoes a conformational change in the linker domain and a displacement of the part of the TRP domain closest to S6. The helices of the HLH region in TRPV2 assume a similar conformation to that observed in the open TRPV1, but the connecting loop is in a different position. The position of the TRP domain in TRPV2 is different from that in both closed and open TRPV1. Green arrows indicate the motions of the open TRPV1 S6 and the linker domain (HLH) compared to the closed TRPV1 and TRPV2, respectively. (c) Comparison of the coupling between S6 and the TRP domain in the open (green) TRPV1 and the TRPV2 (blue) channels. The positions of π-helices in both S6 and the junction between S5 and the S4-S5 linker in TRPV1 are indicated (red dots).
Figure 5
Figure 5
Putative lipid densities in the TRPV2 map. The cartoon shows the location of the density peaks in the global context. (a) View showing the density (purple) observed in the pocket between subunits formed by S4 and the S4-S5 linker of one subunit and S5 and S6 of the adjacent subunit, as well as the 310 helical segment observed in the lower part of S4 (S4b). (b) Density above the coupling domain–TRP domain nexus, between helices S1 and S2. (c) A cholesterol molecule docked into the density with two possible orientations, with a local CC of 0.65 (top) and 0.51 (bottom) between the reciprocal-space reflections filtered at 4 Å and the docked cholesterol molecule. S2 and S3 were removed for clarity.
Figure 6
Figure 6
Coupling between the TRP domain and S6. (a) Top view of the closed TRPV1, open TRPV1 and TRPV2 structures. S1–S5 have been removed for simplicity. Rotation of ARD (cyan) leads to a displacement of the TRP domain (red), which pulls on the S6 (blue) and thereby drives the opening of the lower gate. In TRPV2, the coupling between S6 and the TRP domain is disrupted, and the ARD rotation is therefore not translated to an opening of the channel. (b) Cartoon of the proposed gating mechanism in TRPV channels. The rotation of ARD (light blue circle) is directly coupled to opening of the lower gate through the TRP domain (red). This coupling is guided by the pre-S1 helix, the linker domain and CTD, which we collectively refer to as the ‘coupling domain’ (yellow square).
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References

    1. Ramsey IS, Delling M, Clapham DE. An introduction to TRP channels. Annu. Rev. Physiol. 2006;68:619–647. - PubMed
    1. Bandell M, Macpherson LJ, Patapoutian A. From chills to chilis: mechanisms for thermosensation and chemesthesis via thermoTRPs. Curr. Opin. Neurobiol. 2007;17:490–497. - PMC - PubMed
    1. Caterina MJ, et al. The capsaicin receptor: a heat-activated ion channel in the pain pathway. Nature. 1997;389:816–824. - PubMed
    1. Julius D. TRP channels and pain. Annu. Rev. Cell Dev. Biol. 2013;29:355–384. - PubMed
    1. Cao E, Cordero-Morales JF, Liu B, Qin F, Julius D. TRPV1 channels are intrinsically heat sensitive and negatively regulated by phosphoinositide lipids. Neuron. 2013;77:667–679. - PMC - PubMed

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