TY - JOUR
T1 - The membrane protein Pannexin1 forms two open-channel conformations depending on the mode of activation
AU - Wang, Junjie
AU - Ambrosi, Cinzia
AU - Qiu, Feng
AU - Jackson, David G.
AU - Sosinsky, Gina
AU - Dahl, Gerhard
PY - 2014/7/22
Y1 - 2014/7/22
N2 - Pannexin1 (Panx1) participates in several signaling events that involve adenosine triphosphate (ATP) release, including the innate immune response, ciliary beat in airway epithelia, and oxygen supply in the vasculature. The view that Panx1 formsa large ATP release channel has been challenged by the association of a low-conductance, small anion-selective channel with the presence of Panx1. We showed that Panx1 membrane channels can function in two distinct modes with different conductances and permeabilities when heterologously expressed in Xenopus oocytes. When stimulated by potassium ions (K+), Panx1 formed a high-conductance channel of ∼500 pS that was permeable to ATP. Various physiological stimuli can induce this ATP-permeable conformation of the channel in several cell types. In contrast, the channel had a low conductance (∼50 pS) with no detectable ATP permeability when activated by voltage in the absence of K+. The two channel states were associated with different reactivities of the terminal cysteine of Panx1 to thiol reagents, suggesting different conformations. Single-particle electron microscopic analysis revealed that K+ stimulated the formation of channels with a larger pore diameter than those formed in the absence of K+. These data suggest that different stimuli lead to distinct channel structures with distinct biophysical properties.
AB - Pannexin1 (Panx1) participates in several signaling events that involve adenosine triphosphate (ATP) release, including the innate immune response, ciliary beat in airway epithelia, and oxygen supply in the vasculature. The view that Panx1 formsa large ATP release channel has been challenged by the association of a low-conductance, small anion-selective channel with the presence of Panx1. We showed that Panx1 membrane channels can function in two distinct modes with different conductances and permeabilities when heterologously expressed in Xenopus oocytes. When stimulated by potassium ions (K+), Panx1 formed a high-conductance channel of ∼500 pS that was permeable to ATP. Various physiological stimuli can induce this ATP-permeable conformation of the channel in several cell types. In contrast, the channel had a low conductance (∼50 pS) with no detectable ATP permeability when activated by voltage in the absence of K+. The two channel states were associated with different reactivities of the terminal cysteine of Panx1 to thiol reagents, suggesting different conformations. Single-particle electron microscopic analysis revealed that K+ stimulated the formation of channels with a larger pore diameter than those formed in the absence of K+. These data suggest that different stimuli lead to distinct channel structures with distinct biophysical properties.
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U2 - 10.1126/scisignal.2005431
DO - 10.1126/scisignal.2005431
M3 - Article
C2 - 25056878
AN - SCOPUS:84906827762
VL - 7
JO - Science's STKE : signal transduction knowledge environment
JF - Science's STKE : signal transduction knowledge environment
SN - 1937-9145
IS - 335
M1 - ra69
ER -