title: Characterization of ATPase Activity of P2RX2 Cation Channel.
abstract: 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.
authors.affiliation: Department of Otolaryngology, University of Miami Miller School of Medicine Miami, FL, USA.
authors.forename: Rahul
authors.initials: R
authors.lastname: Mittal
authors.affiliation: Department of Otolaryngology, University of Miami Miller School of Medicine Miami, FL, USA.
authors.forename: M'hamed
authors.initials: M
authors.lastname: Grati
authors.affiliation: Laboratory of Cell Structure and Dynamics, Section on Structural Cell Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health Bethesda, MD, USA.
authors.forename: Miloslav
authors.initials: M
authors.lastname: Sedlacek
authors.affiliation: Department of Biochemistry, University of Miami Leonard M. Miller School of Medicine Miami, FL, USA.
authors.forename: Fenghua
authors.initials: F
authors.lastname: Yuan
authors.affiliation: Department of Otolaryngology, Emory University Atlanta, GA, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Chang
authors.affiliation: Department of Otolaryngology, University of Miami Miller School of Medicine Miami, FL, USA.
authors.forename: Denise
authors.initials: D
authors.lastname: Yan
authors.affiliation: Department of Otolaryngology, Emory University Atlanta, GA, USA.
authors.forename: Xi
authors.initials: X
authors.lastname: Lin
authors.affiliation: Laboratory of Cell Structure and Dynamics, Section on Structural Cell Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health Bethesda, MD, USA.
authors.forename: Bechara
authors.initials: B
authors.lastname: Kachar
authors.affiliation: Department of Biochemistry, University of Miami Leonard M. Miller School of Medicine Miami, FL, USA.
authors.forename: Amjad
authors.initials: A
authors.lastname: Farooq
authors.affiliation: Department of Physics, Florida International University Miami, FL, USA.
authors.forename: Prem
authors.initials: P
authors.lastname: Chapagain
authors.affiliation: Department of Biochemistry, University of Miami Leonard M. Miller School of Medicine Miami, FL, USA.
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Otolaryngology, University of Miami Miller School of MedicineMiami, FL, USA; Department of Biochemistry, University of Miami Leonard M. Miller School of MedicineMiami, FL, USA; Department of Otolaryngology, Central South University, Xiangya HospitalChangsha, China.
authors.forename: Xue Z
authors.initials: XZ
authors.lastname: Liu
keywords: ATPase activity; Electrophysiology; Ligand-gated ion channels; P2X2; computer modeling