Protein kinase A (PKA) is central for forward transport of two pore domain potassium channels K2P3.1 and K2P9.1
Protein kinase A (PKA) is central for forward transport of two pore domain potassium channels K2P3.1 and K2P9.1
Acid sensitive two-pore domain potassium channels (K2P3.1 and K2P9.1) play key roles in both physiological and pathophysiological mechanisms, the most fundamental of which is control of resting membrane potential of cells in which they are expressed. These background leak channels are constitutively active once expressed at the plasma membrane and hence tight control of their targeting and surface expression is fundamental to the regulation of K+ flux and cell excitability. The chaperone protein, 14-3-3, binds to a critical phosphorylated serine in the channel C-termini of K2P3.1 and K2P9.1 (S393 and S373, respectively) and overcomes retention in the endoplasmic reticulum by ?COP. We sought to identify the kinase responsible for phosphorylation of the terminal serine in human and rat variants of K2P3.1 and K2P9.1. Adopting a bioinformatic approach, three candidate protein kinases were identified: cAMP-dependent protein kinase (PKA), ribosomal S6 kinase (RSK) and protein kinase C (PKC). In vitro phosphorylation assays were utilised to determine the ability of the candidate kinases to phosphorylate the channel C-termini. Electrophysiological measurements of human K2P3.1 transiently expressed in HEK293 cells and cell surface assays of GFP-tagged K2P3.1 and K2P9.1 enabled the functional implications of phosphorylation by specific kinases to be determined. All our findings support the conclusion that PKA is responsible for the phosphorylation of the terminal serine in both K2P3.1 and K2P9.1.
chaperone chaperonin, potassium channels, protein export, protein kinase a (pka), protein phosphorylation14-3-3k<inf>2p</inf>3.1/task1k<inf>2p</inf>9.1/task3, phos-tag, phosphorylation prediction
14110-14119
Mant, Alexandra
63319e45-deeb-45ad-a30d-e05b42052a0d
Elliott, David
39970a0b-5732-41d9-acf8-6886af2d10ed
Eyers, Patrick A.
386b928f-da14-4e6a-9ddf-c73b86802791
O'Kelly, Ita M.
e640f28a-42f0-48a6-9ce2-cb5a85d08c66
22 April 2011
Mant, Alexandra
63319e45-deeb-45ad-a30d-e05b42052a0d
Elliott, David
39970a0b-5732-41d9-acf8-6886af2d10ed
Eyers, Patrick A.
386b928f-da14-4e6a-9ddf-c73b86802791
O'Kelly, Ita M.
e640f28a-42f0-48a6-9ce2-cb5a85d08c66
Mant, Alexandra, Elliott, David, Eyers, Patrick A. and O'Kelly, Ita M.
(2011)
Protein kinase A (PKA) is central for forward transport of two pore domain potassium channels K2P3.1 and K2P9.1.
The Journal of Biological Chemistry, 286 (16), .
(doi:10.1074/jbc.M110.190702).
(PMID:21357689)
Abstract
Acid sensitive two-pore domain potassium channels (K2P3.1 and K2P9.1) play key roles in both physiological and pathophysiological mechanisms, the most fundamental of which is control of resting membrane potential of cells in which they are expressed. These background leak channels are constitutively active once expressed at the plasma membrane and hence tight control of their targeting and surface expression is fundamental to the regulation of K+ flux and cell excitability. The chaperone protein, 14-3-3, binds to a critical phosphorylated serine in the channel C-termini of K2P3.1 and K2P9.1 (S393 and S373, respectively) and overcomes retention in the endoplasmic reticulum by ?COP. We sought to identify the kinase responsible for phosphorylation of the terminal serine in human and rat variants of K2P3.1 and K2P9.1. Adopting a bioinformatic approach, three candidate protein kinases were identified: cAMP-dependent protein kinase (PKA), ribosomal S6 kinase (RSK) and protein kinase C (PKC). In vitro phosphorylation assays were utilised to determine the ability of the candidate kinases to phosphorylate the channel C-termini. Electrophysiological measurements of human K2P3.1 transiently expressed in HEK293 cells and cell surface assays of GFP-tagged K2P3.1 and K2P9.1 enabled the functional implications of phosphorylation by specific kinases to be determined. All our findings support the conclusion that PKA is responsible for the phosphorylation of the terminal serine in both K2P3.1 and K2P9.1.
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Accepted/In Press date: 28 February 2011
Published date: 22 April 2011
Keywords:
chaperone chaperonin, potassium channels, protein export, protein kinase a (pka), protein phosphorylation14-3-3k<inf>2p</inf>3.1/task1k<inf>2p</inf>9.1/task3, phos-tag, phosphorylation prediction
Organisations:
Human Genetics
Identifiers
Local EPrints ID: 176303
URI: http://eprints.soton.ac.uk/id/eprint/176303
ISSN: 0021-9258
PURE UUID: 5c6aad5c-549a-4ee9-aed9-e9fec53138d4
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Date deposited: 22 Mar 2011 14:45
Last modified: 14 Mar 2024 02:49
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Contributors
Author:
Alexandra Mant
Author:
David Elliott
Author:
Patrick A. Eyers
Author:
Ita M. O'Kelly
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