Triple arginine residues in the proximal C-terminus of TREK K+ channels are critical for biphasic regulation by phosphatidylinositol 4,5-bisphosphate
| العنوان: | Triple arginine residues in the proximal C-terminus of TREK K+ channels are critical for biphasic regulation by phosphatidylinositol 4,5-bisphosphate |
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| المؤلفون: | Joo Hyun Nam, Sung Joon Kim, Yin Hua Zhang, Joohan Woo, Young Keul Jeon, Dong Hoon Shin |
| المصدر: | American Journal of Physiology-Cell Physiology. 316:C312-C324 |
| بيانات النشر: | American Physiological Society, 2019. |
| سنة النشر: | 2019 |
| مصطلحات موضوعية: | chemistry.chemical_compound, Arginine, chemistry, Phosphatidylinositol 4,5-bisphosphate, Physiology, C-terminus, Intracellular pH, Domain (ring theory), Biophysics, Arachidonic acid, Cell Biology, Phosphatidylinositol, K channels |
| الوصف: | TWIK-related two-pore domain K+ channels (TREKs) are activated by acidic intracellular pH (pHi), membrane stretch, temperature, and arachidonic acid (AA). Phosphatidylinositol 4,5-bisphosphate (PIP2) exerts concentration-dependent biphasic regulations, which have been observed: inhibition by high PIP2, activation by partial decrease of PIP2, and inhibition by depletion of PIP2. Consistently, the stimulation of voltage-sensitive PIP2 phosphatase (Dr-VSP) induces initial activation and subsequent inhibition of TREKs. Lys in the proximal C-terminus (pCt) is responsible for the inhibition by high PIP2, which is generated by phosphatidylinositol kinases with ATP; its neutralizing mutation [K330A of human TREK-2 (hTREK-2)] induces tonic high activity, irrespective of ATP. Here we focus on triple successive Arg in pCt (R3-pCt) as a candidate region for the stimulatory regulation by lower PIP2. Their neutralized mutant (R3A-pCt; RRR340-2A and RRR355-7A in hTREK-1 and -2, respectively) showed negligible basal current and was not affected by ATP removal or by Dr-VSP activation. Phosphatidic acid, a phospholipid agonist of TREKs, did not activate R3A-pCt. In contrast, acidic pHi, AA, and high temperature activated R3A-pCt normally, whereas activation by membrane stretch was attenuated. In hTREK-2, combined neutralizations of the inhibitory K330 and R3-pCt (K330A/RRR355-7A) did not recover the suppressed current. In contrast, combined neutralization of pHi-sensing Glu (E332A/R355-7A) induced tonic high current and no further activation by pHi. Interestingly, when the Gly between K330/E332 and R3-pCt was mutated (G334A), hTREK-2 was tonic activated with reversed responses to ATP and acidic pHi. Therefore, we propose that the PIP2-dependent converse regulation of TREKs by Lys and R3-pCt with Gly implies structural flexibility. |
| تدمد: | 1522-1563 0363-6143 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_________::fee41b138fa830edc2420163b25bad74Test https://doi.org/10.1152/ajpcell.00417.2018Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi...........fee41b138fa830edc2420163b25bad74 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15221563 03636143 |
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