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The Exceptionally High Reactivity Of Cys 621 Is Critical For Electrophilic Activation Of The Sensory Nerve Ion Channel Trpa1, Parmvir K. Bahia, Thomas A. Parks, Katherine R. Stanford, David A. Mitchell, Sameer Varma, Stanley M. Stevens Jr., Thomas E. Taylor-Clark

Molecular Biosciences Faculty Publications

Activation of the sensory nerve ion channel TRPA1 by electrophiles is the key mechanism that initiates nociceptive signaling, and leads to defensive reflexes and avoidance behaviors, during oxidative stress in mammals. TRPA1 is rapidly activated by subtoxic levels of electrophiles, but it is unclear how TRPA1 outcompetes cellular antioxidants that protect cytosolic proteins from electrophiles. Here, using physiologically relevant exposures, we demonstrate that electrophiles react with cysteine residues on mammalian TRPA1 at rates that exceed the reactivity of typical cysteines by 6,000-fold and that also exceed the reactivity of antioxidant enzymes. We show that TRPA1 possesses a complex reactive cysteine …