Regulated phosphorylation of the K-Cl cotransporter KCC3 at dual C-terminal threonines is a potent switch of intracellular potassium content and cell volume homeostasis
The defense of cell volume against excessive shrinkage or swelling is a requirement for cell function and organismal survival. Cell swelling triggers a coordinated homeostatic response termed regulatory volume decrease (RVD), resulting in K+ and Cl– efflux via the activation of K+ channels, volume-r...
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| Format: | Article |
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Frontiers Media S.A.
2015-07-01
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| Series: | Frontiers in Cellular Neuroscience |
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| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fncel.2015.00255/full |
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| author | Norma C. Adragna Nagendra Babu Ravilla Peter K. Lauf Peter K. Lauf Gulnaz eBegum Arjun R. Khanna Dandan eSun Dandan eSun Kristopher T Kahle Kristopher T Kahle |
| author_facet | Norma C. Adragna Nagendra Babu Ravilla Peter K. Lauf Peter K. Lauf Gulnaz eBegum Arjun R. Khanna Dandan eSun Dandan eSun Kristopher T Kahle Kristopher T Kahle |
| author_sort | Norma C. Adragna |
| collection | DOAJ |
| description | The defense of cell volume against excessive shrinkage or swelling is a requirement for cell function and organismal survival. Cell swelling triggers a coordinated homeostatic response termed regulatory volume decrease (RVD), resulting in K+ and Cl– efflux via the activation of K+ channels, volume-regulated anion channels (VRACs), and the K+-Cl– cotransporters, including KCC3. Here, we show genetic alanine (Ala) substitution at threonines (Thr) 991 and 1048 in the KCC3a isoform carboxyl-terminus, preventing inhibitory phosphorylation at these sites, not only significantly up-regulates KCC3a activity up to 25-fold in normally inhibitory isotonic conditions, but is also accompanied by reversal of activity of the related bumetanide-sensitive Na+-K+-2Cl– cotransporter isoform 1 (NKCC1). This results in a rapid (<10 min) and significant (>90 %) reduction in intracellular K+ content (Ki) via both Cl-dependent (KCC3a + NKCC1) and Cl-independent (DCPIB [VRAC inhibitor]-sensitive) pathways, which collectively renders cells less prone to acute swelling in hypotonic osmotic stress. Together, these data demonstrate the phosphorylation state of Thr991/Thr1048 in the KCC3a encodes a potent switch of transporter activity, Ki homeostasis, and cell volume regulation, and reveal novel observations into the functional interaction among ion transport molecules involved in RVD. |
| first_indexed | 2024-12-10T09:16:44Z |
| format | Article |
| id | doaj.art-d7541586602344ff85071e4a8e5883d6 |
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| issn | 1662-5102 |
| language | English |
| last_indexed | 2024-12-10T09:16:44Z |
| publishDate | 2015-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Cellular Neuroscience |
| spelling | doaj.art-d7541586602344ff85071e4a8e5883d62022-12-22T01:54:51ZengFrontiers Media S.A.Frontiers in Cellular Neuroscience1662-51022015-07-01910.3389/fncel.2015.00255145630Regulated phosphorylation of the K-Cl cotransporter KCC3 at dual C-terminal threonines is a potent switch of intracellular potassium content and cell volume homeostasisNorma C. Adragna0Nagendra Babu Ravilla1Peter K. Lauf2Peter K. Lauf3Gulnaz eBegum4Arjun R. Khanna5Dandan eSun6Dandan eSun7Kristopher T Kahle8Kristopher T Kahle9Boonshoft School of Medicine, Wright State UniversityBoonshoft School of Medicine, Wright State UniversityBoonshoft School of Medicine, Wright State UniversityBoonshoft School of Medicine, Wright State UniversityUniversity of PittsburghChildren's Hospital BostonUniversity of PittsburghVeterans Affairs Pittsburgh Health Care SystemChildren's Hospital BostonHarvard Medical SchoolThe defense of cell volume against excessive shrinkage or swelling is a requirement for cell function and organismal survival. Cell swelling triggers a coordinated homeostatic response termed regulatory volume decrease (RVD), resulting in K+ and Cl– efflux via the activation of K+ channels, volume-regulated anion channels (VRACs), and the K+-Cl– cotransporters, including KCC3. Here, we show genetic alanine (Ala) substitution at threonines (Thr) 991 and 1048 in the KCC3a isoform carboxyl-terminus, preventing inhibitory phosphorylation at these sites, not only significantly up-regulates KCC3a activity up to 25-fold in normally inhibitory isotonic conditions, but is also accompanied by reversal of activity of the related bumetanide-sensitive Na+-K+-2Cl– cotransporter isoform 1 (NKCC1). This results in a rapid (<10 min) and significant (>90 %) reduction in intracellular K+ content (Ki) via both Cl-dependent (KCC3a + NKCC1) and Cl-independent (DCPIB [VRAC inhibitor]-sensitive) pathways, which collectively renders cells less prone to acute swelling in hypotonic osmotic stress. Together, these data demonstrate the phosphorylation state of Thr991/Thr1048 in the KCC3a encodes a potent switch of transporter activity, Ki homeostasis, and cell volume regulation, and reveal novel observations into the functional interaction among ion transport molecules involved in RVD.http://journal.frontiersin.org/Journal/10.3389/fncel.2015.00255/fullChloride ChannelsGABA ModulatorsKCC2neuropathic painAutism Spectrum DisordersNKCC1 |
| spellingShingle | Norma C. Adragna Nagendra Babu Ravilla Peter K. Lauf Peter K. Lauf Gulnaz eBegum Arjun R. Khanna Dandan eSun Dandan eSun Kristopher T Kahle Kristopher T Kahle Regulated phosphorylation of the K-Cl cotransporter KCC3 at dual C-terminal threonines is a potent switch of intracellular potassium content and cell volume homeostasis Frontiers in Cellular Neuroscience Chloride Channels GABA Modulators KCC2 neuropathic pain Autism Spectrum Disorders NKCC1 |
| title | Regulated phosphorylation of the K-Cl cotransporter KCC3 at dual C-terminal threonines is a potent switch of intracellular potassium content and cell volume homeostasis |
| title_full | Regulated phosphorylation of the K-Cl cotransporter KCC3 at dual C-terminal threonines is a potent switch of intracellular potassium content and cell volume homeostasis |
| title_fullStr | Regulated phosphorylation of the K-Cl cotransporter KCC3 at dual C-terminal threonines is a potent switch of intracellular potassium content and cell volume homeostasis |
| title_full_unstemmed | Regulated phosphorylation of the K-Cl cotransporter KCC3 at dual C-terminal threonines is a potent switch of intracellular potassium content and cell volume homeostasis |
| title_short | Regulated phosphorylation of the K-Cl cotransporter KCC3 at dual C-terminal threonines is a potent switch of intracellular potassium content and cell volume homeostasis |
| title_sort | regulated phosphorylation of the k cl cotransporter kcc3 at dual c terminal threonines is a potent switch of intracellular potassium content and cell volume homeostasis |
| topic | Chloride Channels GABA Modulators KCC2 neuropathic pain Autism Spectrum Disorders NKCC1 |
| url | http://journal.frontiersin.org/Journal/10.3389/fncel.2015.00255/full |
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