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Regulation of pro-apoptotic phosphorylation of Kv2.1 K<sup>+</sup> channels

He, K and McCord, MC and Hartnett, KA and Aizenman, E (2015) Regulation of pro-apoptotic phosphorylation of Kv2.1 K<sup>+</sup> channels. PLoS ONE, 10 (6).

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Abstract

© 2015 He et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Caspase activity during apoptosis is inhibited by physiological concentrations of intracellular K<sup>+</sup>. To enable apoptosis in injured cortical and hippocampal neurons, cellular loss of this cation is facilitated by the insertion of Kv2.1 K<sup>+</sup> channels into the plasma membrane via a Zn<sup>2+</sup> /CaMKII/SNARE-dependent process. Pro-apoptotic membrane insertion of Kv2.1 requires the dual phosphorylation of the channel by Src and p38 at cytoplasmic N- and C- terminal residues Y124 and S800, respectively. In this study, we investigate if these phosphorylation sites are mutually co-regulated, and whether putative N- and C-terminal interactions, possibly enabled by Kv2.1 intracellular cysteine residues C73 and C710, influence the phosphorylation process itself. Studies were performed with recombinant wild type and mutant Kv2.1 expressed in Chinese hamster ovary (CHO) cells. Using immunoprecipitated Kv2.1 protein and phospho-specific antibodies, we found that an intact Y124 is required for p38 phosphorylation of S800, and, importantly, that Src phosphorylation of Y124 facilitates the action of the p38 at the S800 residue. Moreover, the actions of Src on Kv2.1 are substantially decreased in the non-phosphorylatable S800A channel mutant. We also observed that mutations of either C73 or C710 residues decreased the p38 phosphorylation at S800 without influencing the actions of Src on tyrosine phosphorylation of Kv2.1. Surprisingly, however, apoptotic K<sup>+</sup> currents were suppressed only in cells expressing the Kv2.1(C73A) mutant but not in those transfected with Kv2.1(C710A), suggesting a possible structural alteration in the C-terminal mutant that facilitates membrane insertion. These results show that intracellular N-terminal domains critically regulate phosphorylation of the C-terminal of Kv2.1, and vice versa, suggesting possible new avenues for modifying the apoptotic insertion of these channels during neurodegenerative processes.


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Details

Item Type: Article
Status: Published
Creators/Authors:
CreatorsEmailPitt UsernameORCID
He, Kkaihe@pitt.eduKAIHE
McCord, MC
Hartnett, KA
Aizenman, Eredox@pitt.eduREDOX
Contributors:
ContributionContributors NameEmailPitt UsernameORCID
EditorAttali, BernardUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Date: 26 June 2015
Date Type: Publication
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Journal or Publication Title: PLoS ONE
Volume: 10
Number: 6
DOI or Unique Handle: 10.1371/journal.pone.0129498
Institution: University of Pittsburgh
Schools and Programs: School of Medicine > Neurobiology
Refereed: Yes
Date Deposited: 29 Jun 2016 16:22
Last Modified: 26 Jan 2019 17:55
URI: http://d-scholarship.pitt.edu/id/eprint/28430

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