Insights into the channel gating of P2X receptors from structures, dynamics and small molecules

Wang, Jin; Yu, Ye

doi:10.1038/aps.2015.127

Cited by 38 publications

(23 citation statements)

References 139 publications

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“…Recently, a number of crystal structures representing different P2X receptor isoforms and active states were made available (9-11, 18, 28, 29). These structures suggest that multiple allosteric changes may be associated with ATP binding to channel gating (27,(30)(31)(32)(33)(34)(35), and, presumably, each of the allosteric changes can be targeted by small molecules for functional perturbation. However, it remains challenging to define the function of a potential allosteric site, identify the drug, and determine the drug's mechanism of action at the specific site (36,37).…”

Section: Discussionmentioning

confidence: 99%

Druggable negative allosteric site of P2X3 receptors

Wang

Cui

et al. 2018

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

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Allosteric modulation provides exciting opportunities for drug discovery of enzymes, ion channels, and G protein-coupled receptors. As cation channels gated by extracellular ATP, P2X receptors have attracted wide attention as new drug targets. Although small molecules targeting P2X receptors have entered into clinical trials for rheumatoid arthritis, cough, and pain, negative allosteric modulation of these receptors remains largely unexplored. Here, combining X-ray crystallography, computational modeling, and functional studies of channel mutants, we identified a negative allosteric site on P2X3 receptors, fostered by the left flipper (LF), lower body (LB), and dorsal fin (DF) domains. Using two structurally analogous subtype-specific allosteric inhibitors of P2X3, AF-353 and AF-219, the latter being a drug candidate under phase II clinical trials for refractory chronic cough and idiopathic pulmonary fibrosis, we defined the molecular interactions between the drugs and receptors and the mechanism by which allosteric changes in the LF, DF, and LB domains modulate ATP activation of P2X3. Our detailed characterization of this druggable allosteric site should inspire new strategies to develop P2X3-specific allosteric modulators for clinical use.

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Section: Discussionmentioning

confidence: 99%

Druggable negative allosteric site of P2X3 receptors

Wang

Cui

et al. 2018

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

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“…Out of these seven receptors, P2RX2 is an ATP-gated trimeric ion channel that plays an important role in sound transduction and auditory neurotransmission in the inner ear (Housley et al, 2002 , 2013 ; Järlebark et al, 2002 ; Wang et al, 2003 ; Yan et al, 2013 ). ATP binding to the extracellular loop of the channel is thought to cause conformational changes that trigger channel pore opening and cation internalization (North, 2002 ; Roberts et al, 2006 ; Stelmashenko et al, 2012 ; Mittal et al, 2016 ; Wang and Yu, 2016 ). However, it is not known whether ATP binding or hydrolysis is required for the P2X2 activation.…”

Section: Introductionmentioning

confidence: 99%

Characterization of ATPase Activity of P2RX2 Cation Channel

et al. 2016

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P2X purinergic receptors are plasma membrane ATP-dependent cation channels that are broadly distributed in the mammalian tissues. P2RX2 is a modulator of auditory sensory hair cell mechanotransduction and plays an important role in hair cell tolerance to noise. In this study, we demonstrate for the first time in vitro and in cochlear neuroepithelium, that P2RX2 possesses the ATPase activity. We observed that the P2RX2 V60L human deafness mutation alters its ability to bind ATP, while the G353R has no effect on ATP binding or hydrolysis. A non-hydrolysable ATP assay using HEK293 cells suggests that ATP hydrolysis plays a significant role in the opening and gating of the P2RX2 ion channel. Moreover, the results of structural modeling of the molecule was in agreement with our experimental observations. These novel findings suggest the intrinsic ATPase activity of P2RX2 and provide molecular insights into the channel opening.

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“…The structural comparison of the closed and open structures suggests a possible gating mechanism of P2X receptors (Fig. 1, A and B) (9,16,23,24). First, at the ATP-binding site, ATP promotes the jaw closure between the head and dorsal fin (DF) 3 domains, making the DF domain move upward to the head domain to accommodate ATP.…”

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confidence: 99%

“…Recent studies (22,31) also suggested that the TM region was distorted due to the unexpected absence of intersubunit interactions in the X-ray open structure of zfP2X4 receptor. Thus, although the apo/closed and ATP-bound open X-ray structures of the zfP2X4 receptor have provided a blueprint for the mechanism of P2X activation, the detailed conformational transition during channel gating requires further exploration (18,22,24,31,32,37,39,40).…”

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Intersubunit physical couplings fostered by the left flipper domain facilitate channel opening of P2X4 receptors

Wang

Sun

Cui

et al. 2017

Journal of Biological Chemistry

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P2X receptors are ATP-gated trimeric channels with important roles in diverse pathophysiological functions. A detailed understanding of the mechanism underlying the gating process of these receptors is thus fundamentally important and may open new therapeutic avenues. The left flipper (LF) domain of the P2X receptors is a flexible loop structure, and its coordinated motions together with the dorsal fin (DF) domain are crucial for the channel gating of the P2X receptors. However, the mechanism underlying the crucial role of the LF domain in the channel gating remains obscure. Here, we propose that the ATP-induced allosteric changes of the LF domain enable it to foster intersubunit physical couplings among the DF and two lower body domains, which are pivotal for the channel gating of P2X4 receptors. Metadynamics analysis indicated that these newly established intersubunit couplings correlate well with the ATP-bound open state of the receptors. Moreover, weakening or strengthening these physical interactions with engineered intersubunit metal bridges remarkably decreased or increased the open probability of the receptors, respectively. Further disulfide cross-linking and covalent modification confirmed that the intersubunit physical couplings among the DF and two lower body domains fostered by the LF domain at the open state act as an integrated structural element that is stringently required for the channel gating of P2X4 receptors. Our observations provide new mechanistic insights into P2X receptor activation and will stimulate development of new allosteric modulators of P2X receptors.

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Insights into the channel gating of P2X receptors from structures, dynamics and small molecules

Cited by 38 publications

References 139 publications

Druggable negative allosteric site of P2X3 receptors

Druggable negative allosteric site of P2X3 receptors

Characterization of ATPase Activity of P2RX2 Cation Channel

Intersubunit physical couplings fostered by the left flipper domain facilitate channel opening of P2X4 receptors

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