Regulated phosphorylation of the K-Cl cotransporter KCC3 is a molecular switch of intracellular potassium content and cell volume homeostasis

View/ Open
Author
Adragna, Norma C.
Ravilla, Nagendra B.
Lauf, Peter K.
Begum, Gulnaz
Sun, Dandan
Published Version
https://doi.org/10.3389/fncel.2015.00255Metadata
Show full item recordCitation
Adragna, Norma C., Nagendra B. Ravilla, Peter K. Lauf, Gulnaz Begum, Arjun R. Khanna, Dandan Sun, and Kristopher T. Kahle. 2015. “Regulated phosphorylation of the K-Cl cotransporter KCC3 is a molecular switch of intracellular potassium content and cell volume homeostasis.” Frontiers in Cellular Neuroscience 9 (1): 255. doi:10.3389/fncel.2015.00255. http://dx.doi.org/10.3389/fncel.2015.00255.Abstract
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 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 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.Other Sources
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4496573/pdf/Terms of Use
This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAACitable link to this page
http://nrs.harvard.edu/urn-3:HUL.InstRepos:17820780
Collections
- HMS Scholarly Articles [17714]
Contact administrator regarding this item (to report mistakes or request changes)