We studied the phosphorylation of the secretory Na(+)-K(+)-2Cl(-) cotransporter (NKCC1) in rat parotid acinar cells. We have previously shown that NKCC1 activity in these cells is dramatically upregulated in response to beta-adrenergic stimulation and that this upregulation correlates with NKCC1 phosphorylation, possibly due to protein kinase A (PKA). We show here that when ATP is added to puri...

GABA excites immature neurons due to their relatively high intracellular chloride concentration. This initial high concentration is commonly attributed to the ubiquitous chloride cotransporter NKCC1, which uses a sodium gradient to accumulate chloride. Here we tested this hypothesis in immature retinal amacrine and ganglion cells. Western blotting detected NKCC1 at birth and its expression firs...

Aldosterone increases cation transport and contractility of vascular smooth muscle, but the specific transporter involved and how it is linked to smooth muscle tone is unknown. Because the Na-K-2Cl cotransporter (NKCC1) contributes to vascular smooth muscle contraction and is regulated by vasoactive compounds, we sought to determine whether this transporter is a target of aldosterone in rat aor...

Na+:K+:2Cl- cotransporters (NKCCs) belong to the SLC12A family of cation-coupled Cl- transporters. We investigated whether enamel-producing mouse ameloblasts express NKCCs. Transcripts for Nkcc1 were identified in the mouse dental epithelium by RT-qPCR and NKCC1 protein was immunolocalized in outer enamel epithelium and in the papillary layer but not the ameloblast layer. In incisors of Nkcc1-n...

Muscle wasting or sarcopenia contributes to morbidity and mortality in patients with cancer, renal failure, or heart failure, and in elderly individuals. Na+-K+-2Cl- cotransporter 1 (NKCC1) is highly expressed in mammalian skeletal muscle, where it contributes to the generation of membrane ion currents and potential. However, the physiologic function of NKCC1 in myogenesis is unclear. We invest...

We previously reported that the bumetanide-sensitive Na(+)-K(+)-2Cl- cotransporter (NKCC1) is involved in the hepatic Na+ and K+ sensor mechanism. In the present study, we examined the effects of a high-NaCl or high-KCl diet on hepatic Na+ and K+ receptor sensitivity and NKCC1 expression in the liver of Sprague-Dawley rats. RT-PCR and Western blots were used to measure NKCC1 mRNA and protein ex...

T he ubiquitous Na+,K+,2Cl− cotransporter (NKCC1) belongs to the superfamily of Cl−-coupled carriers providing electroneutral symport of monovalent ions. In vascular smooth muscle cells (VSMC), highceiling diuretics such as furosemide and bumetanide, known to be potent inhibitors of these carriers, decrease the concentration of intracellular chloride ([Cl]i), hyperpolarize the sarcolemma and at...

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 betw...

In the present study, we have demonstrated functional interaction between Ste20-related proline-alanine-rich kinase (SPAK), WNK4 [with no lysine (K)], and the widely expressed Na+-K+-2Cl- cotransporter type 1 (NKCC1). NKCC1 function, which we measured in Xenopus laevis oocytes under both isosmotic (basal) and hyperosmotic (stimulated) conditions, was unaffected when SPAK and WNK4 were expressed...

After peripheral nerve injury, axons are able to regenerate, although specific sensory reinnervation and functional recovery are usually worse for large myelinated than for small sensory axons. The mechanisms that mediate the regeneration of different sensory neuron subpopulations are poorly known. The Na(+)-K(+)-Cl(-) cotransporter 1 (NKCC1) is particularly relevant in setting the intracellula...