Previous work from our laboratory and others has established that Ste-20-related proline-alanine-rich kinase (SPAK/PASK) is central to the regulation of NKCC1 function. With no lysine (K) kinase (WNK4) has also been implicated in the regulation of NKCC1 activity through upstream activation of SPAK. Because previous studies from our laboratory also demonstrated a protein-protein interaction between SPAK and apoptosis-associated tyrosine kinase (AATYK), we explore here the possibility that AATYK is another component of the regulation of NKCC1. Heterologous expression of AATYK1 in NKCC1-injected Xenopus laevis oocytes markedly inhibited cotransporter activity under isosmotic conditions. Interestingly, mutation of key residues in the catalytic domain of AATYK1 revealed that the kinase activity does not play a role in the suppression of NKCC1 function. However, mutagenesis of the two SPAK-binding motifs in AATYK1 completely abrogated this effect. As protein phosphatase 1 (PP1) also plays a central role in the dephosphorylation and inactivation of NKCC1, we investigated the possibility that AATYK1 interacts with the phosphatase. We identified a PP1 docking motif in AATYK1 and demonstrated interaction using yeast-2-hybrid analysis. Mutation of a key valine residue (V1175) within this motif prevented protein-protein interaction. Furthermore, the physical interaction between PP1 and AATYK was required for inhibition of NKCC1 activity in Xenopus laevis oocytes. Taken together, our data are consistent with AATYK1 indirectly inhibiting the SPAK/WNK4 activation of the cotransporter by scaffolding an inhibitory phosphatase in proximity to a stimulatory kinase.
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http://dx.doi.org/10.1152/ajpcell.00580.2006 | DOI Listing |
CNS Neurosci Ther
October 2024
Department of Neurology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
Background: Hydrocephalus is characterized by secretion, circulation, and absorption disorder of cerebrospinal fluid (CSF) with high morbidity and complication rate. The relationship between inflammation and abnormal secretion of CSF by choroid plexus epithelium (CPE) had received more attention. In this study, we aim to detect the role of Toll-like receptor 4/nuclear factor-kappa B/Na+/K+/2Cl-cotransporter 1(TLR4/NF-κB/NKCC1) signal pathway in the development of hydrocephalus.
View Article and Find Full Text PDFInt J Mol Sci
September 2024
Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Sevilla, Spain.
Sci Transl Med
September 2024
Department of Neurobiology, University of Texas Medical Branch, Galveston, TX 77555, USA.
Spinal cord injury (SCI) results in acute damage and triggers secondary injury responses with sustained neuronal loss and dysfunction. However, the underlying mechanisms for these delayed neuronal pathologies are not entirely understood. SCI results in the swelling of spinal neurons, but the contribution of cell swelling to neuronal loss and functional deficits after SCI has not been systematically characterized.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
December 2024
Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai 201306, China; National Experimental Teaching Demonstration Centre for Aquatic Sciences, Shanghai Ocean University, Shanghai 201306, China. Electronic address:
The function of Litopenaeus vannamei Na/K/2Cl cotransporter 1 (NKCC1) under nitrite stress was investigated. The full-length cDNA sequence of the L. vannamei NKCC1 gene was cloned using the rapid amplification of cDNA ends (RACE) technique, and the sequence was analysed using bioinformatics tools.
View Article and Find Full Text PDFJ Clin Invest
September 2024
Department of Internal Medicine.
The airway surface liquid (ASL) plays a crucial role in lung defense mechanisms, and its composition and volume are regulated by the airway epithelium. The cystic fibrosis transmembrane conductance regulator (CFTR) is abundantly expressed in a rare airway epithelial cell type called an ionocyte. Recently, we demonstrated that ionocytes can increase liquid absorption through apical CFTR and basolateral barttin/chloride channels, while airway secretory cells mediate liquid secretion through apical CFTR channels and basolateral NKCC1 transporters.
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