KCNK5 is Functionally Down-Regulated Upon Long-Term Hypotonicity in Ehrlich Ascites Tumor Cells

Abstract

Background/Aims: Regulatory volume decrease (RVD) in response to acute cell swelling is well described and KCNK5 (also known as TASK-2 or K_2P5.1) has been shown to be the volume sensitive K⁺ channel in Ehrlich cells. Very little is, on the other hand, known about the effects of long-term hypotonicity on expression and function of KCNK5, thus we have investigated the effect of long-term hypotonicity (24h - 48h) on KCNK5 in Ehrlich cells on the mRNA, protein and physiological levels. Methods: Physiological effects of long-term hypotonicity were measured using patch-clamp and Coulter counter techniques. Expression patterns of KCNK5 on mRNA and protein levels were established using real-time qPCR and western blotting respectively. Results: The maximum swelling-activated current through KCNK5 was significantly decreased upon 48h of hypotonicity and likewise the RVD response was significantly impaired after both 24 and 48h of hypotonic stimulation. No significant differences in the KCNK5 mRNA expression patterns between control and stimulated cells were observed, but a significant decrease in the KCNK5 protein level 48h after stimulation was found. Conclusion: The data suggest that the strong physiological impairment of KCNK5 in Ehrlich cells after long-term hypotonic stimulation is predominantly due to down-regulation of the KCNK5 protein synthesis.

Transcriptome‐wide association study identifies multiple genes and pathways associated with pancreatic cancer

“…KCNK5 (also known as TASK-2 or K2P5.1) has been shown to be the volume sensitive K (+) channel in cells. 31 KCNK5 is expressed in the kidney, liver, stomach, small intestine, colon, and pancreatic acinus. An electrophysiological study indicated that KCNK5 was expressed in human pancreatic ductal adenocarcinoma cell line, and the pH-sensitive K2P subunits coded by KCNK5 were shown to be expressed in pancreatic.…”

“…KCNK5 (also known as TASK‐2 or K2P5.1) has been shown to be the volume sensitive K (+) channel in cells . KCNK5 is expressed in the kidney, liver, stomach, small intestine, colon, and pancreatic acinus.…”

The Volume Activated Potassium Channel KCNK5 is Up-Regulated in Activated Human T Cells, but Volume Regulation is Impaired

“…Reverse transcriptase PCR with SuperScript II (Invitrogen) and oligo(dT) [12][13][14][15][16][17][18] primer (Invitrogen) was used to generate cDNA from the purified mRNA and performed on a Eppendorf Mastercycler as previously described [24]. QPCR was performed using a Stratagene MX4000 real-time PCR system, Brilliant ® II SYBR ® Green QPCR Master Mix (Stratagene, Agilent Technologies) and the following primers: hKCNK5 forward: 5'-ACCACCCACTCATCTTCCAG-3', hKCNK5 reverse: 5'-AGTGCTGGTGAAGGTGGACT-3', hKv1.3 forward: 5'-CACTTCAGGTTTCAGCAGCA-3', hKv1.3 reverse: 5'-TGTCTCCCGGTGGTAGAAGT-3', hKCa3.1 forward: 5'-ACTGGGCACCTTTCAGACAC-3' and KCa3.1 reverse: 5'-ACGTGCTTCTCTGCCTTGTT-3'.…”