Potassium as an intrinsic uncoupler of the plasma membrane H+-ATPase

Michael Gjedde Palmgren; Morten Jeppe Buch-Pedersen

Abstract

The plant plasma membrane proton pump (H(+)-ATPase) is stimulated by potassium, but it has remained unclear whether potassium is actually transported by the pump or whether it serves other roles. We now show that K(+) is bound to the proton pump at a site involving Asp(617) in the cytoplasmic phosphorylation domain, from where it is unlikely to be transported. Binding of K(+) to this site can induce dephosphorylation of the phosphorylated E(1)P reaction cycle intermediate by a mechanism involving Glu(184) in the conserved TGES motif of the pump actuator domain. Our data identify K(+) as an intrinsic uncoupler of the proton pump and suggest a mechanism for control of the H(+)/ATP coupling ratio. K(+)-induced dephosphorylation of E(1)P may serve regulatory purposes and play a role in negative regulation of the transmembrane electrochemical gradient under cellular conditions where E(1)P is accumulating.

Original language	English
Publication date	2006
Number of pages	1
Publication status	Published - 2006
Event	Plant Transporters Meeting - Wye, United Kingdom Duration: 4 Sept 2006 → 6 Sept 2006

Conference

Conference	Plant Transporters Meeting
Country/Territory	United Kingdom
City	Wye
Period	04/09/2006 → 06/09/2006

Cite this

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title = "Potassium as an intrinsic uncoupler of the plasma membrane H+-ATPase",

abstract = "The plant plasma membrane proton pump (H(+)-ATPase) is stimulated by potassium, but it has remained unclear whether potassium is actually transported by the pump or whether it serves other roles. We now show that K(+) is bound to the proton pump at a site involving Asp(617) in the cytoplasmic phosphorylation domain, from where it is unlikely to be transported. Binding of K(+) to this site can induce dephosphorylation of the phosphorylated E(1)P reaction cycle intermediate by a mechanism involving Glu(184) in the conserved TGES motif of the pump actuator domain. Our data identify K(+) as an intrinsic uncoupler of the proton pump and suggest a mechanism for control of the H(+)/ATP coupling ratio. K(+)-induced dephosphorylation of E(1)P may serve regulatory purposes and play a role in negative regulation of the transmembrane electrochemical gradient under cellular conditions where E(1)P is accumulating.",

author = "Palmgren, {Michael Gjedde} and Buch-Pedersen, {Morten Jeppe}",

note = "Sider: 7; Plant Transporters Meeting ; Conference date: 04-09-2006 Through 06-09-2006",

year = "2006",

language = "English",

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TY - ABST

T1 - Potassium as an intrinsic uncoupler of the plasma membrane H+-ATPase

AU - Palmgren, Michael Gjedde

AU - Buch-Pedersen, Morten Jeppe

N1 - Sider: 7

PY - 2006

Y1 - 2006

N2 - The plant plasma membrane proton pump (H(+)-ATPase) is stimulated by potassium, but it has remained unclear whether potassium is actually transported by the pump or whether it serves other roles. We now show that K(+) is bound to the proton pump at a site involving Asp(617) in the cytoplasmic phosphorylation domain, from where it is unlikely to be transported. Binding of K(+) to this site can induce dephosphorylation of the phosphorylated E(1)P reaction cycle intermediate by a mechanism involving Glu(184) in the conserved TGES motif of the pump actuator domain. Our data identify K(+) as an intrinsic uncoupler of the proton pump and suggest a mechanism for control of the H(+)/ATP coupling ratio. K(+)-induced dephosphorylation of E(1)P may serve regulatory purposes and play a role in negative regulation of the transmembrane electrochemical gradient under cellular conditions where E(1)P is accumulating.

AB - The plant plasma membrane proton pump (H(+)-ATPase) is stimulated by potassium, but it has remained unclear whether potassium is actually transported by the pump or whether it serves other roles. We now show that K(+) is bound to the proton pump at a site involving Asp(617) in the cytoplasmic phosphorylation domain, from where it is unlikely to be transported. Binding of K(+) to this site can induce dephosphorylation of the phosphorylated E(1)P reaction cycle intermediate by a mechanism involving Glu(184) in the conserved TGES motif of the pump actuator domain. Our data identify K(+) as an intrinsic uncoupler of the proton pump and suggest a mechanism for control of the H(+)/ATP coupling ratio. K(+)-induced dephosphorylation of E(1)P may serve regulatory purposes and play a role in negative regulation of the transmembrane electrochemical gradient under cellular conditions where E(1)P is accumulating.

M3 - Conference abstract for conference

T2 - Plant Transporters Meeting

Y2 - 4 September 2006 through 6 September 2006

ER -

Potassium as an intrinsic uncoupler of the plasma membrane H⁺-ATPase

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