Calcium permeability of transient receptor potential canonical (TRPC) 4 channels measured by TRPC4-GCaMP6s

Ko, Jung Hwa; Myeong, Jongyun; Yang, Dongki; So, Insuk

doi:10.4196/kjpp.2017.21.1.133

Cited by 14 publications

(11 citation statements)

References 39 publications

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“…The study also uncovered that the application of EA on TRPC4 or 5-overexpressed human embryonic kidney (HEK) cells activates the channels and induces cell death in consequence of increasing intracellular calcium levels [9]. Such results were supported by our previous studies where we reported Gα i , oxidized glutathione and constitutively active mutant of TRPC4, 5 increased intracellular Ca 2+ [3610] and used TRPC4-GCaMP6 to find that EA increased calcium levels near TRPC4 channels [11]. However, the mechanism of EA-induced activation of the ion channels is unclear.…”

Section: Introductionmentioning

confidence: 64%

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Englerin A-sensing charged residues for transient receptor potential canonical 5 channel activation

Jeong

Kim

et al. 2019

Korean J Physiol Pharmacol

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The transient receptor potential canonical (TRPC) 5 channel, known as a nonselective cation channel, has a crucial role in calcium influx. TRPC5 has been reported to be activated by muscarinic receptor activation and extracellular pH change and inhibited by the protein kinase C pathway. Recent studies have also suggested that TRPC5 is extracellularly activated by englerin A (EA), but the mechanism remains unclear. The purpose of this study is to identify the EA-interaction sites in TRPC5 and thereby clarify the mechanism of TRPC5 activation. TRPC5 channels are over-expressed in human embryonic kidney (HEK293) cells. TRPC5 mutants were generated by site-directed mutagenesis. The whole-cell patch-clamp configuration was used to record TRPC5 currents. Western analysis was also performed to observe the expression of TRPC5 mutants. To identify the EA-interaction site in TRPC5, we first generated pore mutants. When screening the mutants with EA, we observed the EA-induced current increases of TRPC5 abolished in K554N, H594N, and E598Q mutants. The current increases of other mutants were reduced in different levels. We also examined the functional intactness of the mutants that had no effect by EA with TRPC5 agonists, such as carbachol or GTPγS. Our results suggest that the three residues, Lys-554, His-594, and Glu-598, in TRPC5 might be responsible for direct interaction with EA, inducing the channel activation. We also suggest that although other pore residues are not critical, they could partly contribute to the EA-induced channel activation.

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Section: Introductionmentioning

confidence: 64%

“…4). We also showed that TRPC4 was activated by EA [11]. In addition, EA activated TRPC1/4 and TRPC1/5 heteromer and induced cell toxicity via Na + influx instead of Ca 2+ influx [1819].…”

Section: Discussionmentioning

confidence: 99%

Englerin A-sensing charged residues for transient receptor potential canonical 5 channel activation

Jeong

Kim

et al. 2019

Korean J Physiol Pharmacol

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“…However, Trpc3 Ca 2+ permeability exceeds that of monovalent cations, i.e., P Ca /P Na > 1 [14,16,46,63], which is inconsistent with a current like I CAN that is selective for monovalent cations yet gated by Ca 2+ . Nevertheless, heteromeric Trpc channels that include Trpc1 diminish Ca 2+ permeability such that P Ca /P Na < 1 [30,64,65]. Trpc3 can form heteromeric channels with Trpc1 [65–68] as well as Trpc6 and Trpc7 [68,69].…”

Section: Discussionmentioning

confidence: 99%

Trpm4 ion channels in pre-Bötzinger complex interneurons are essential for breathing motor pattern but not rhythm

et al. 2019

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Inspiratory breathing movements depend on pre-Bötzinger complex (preBötC) interneurons that express calcium (Ca 2+ )-activated nonselective cationic current ( I CAN ) to generate robust neural bursts. Hypothesized to be rhythmogenic, reducing I CAN is predicted to slow down or stop breathing; its contributions to motor pattern would be reflected in the magnitude of movements (output). We tested the role(s) of I CAN using reverse genetic techniques to diminish its putative ion channels Trpm4 or Trpc3 in preBötC neurons in vivo. Adult mice transduced with Trpm4-targeted short hairpin RNA (shRNA) progressively decreased the tidal volume of breaths yet surprisingly increased breathing frequency, often followed by gasping and fatal respiratory failure. Mice transduced with Trpc3-targeted shRNA survived with no changes in breathing. Patch-clamp and field recordings from the preBötC in mouse slices also showed an increase in the frequency and a decrease in the magnitude of preBötC neural bursts in the presence of Trpm4 antagonist 9-phenanthrol, whereas the Trpc3 antagonist pyrazole-3 (pyr-3) showed inconsistent effects on magnitude and no effect on frequency. These data suggest that Trpm4 mediates I CAN , whose influence on frequency contradicts a direct role in rhythm generation. We conclude that Trpm4-mediated I CAN is indispensable for motor output but not the rhythmogenic core mechanism of the breathing central pattern generator.

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“…The calcium permeability of TRPC4 and TRPC5 channels is changed when TRPC1 subunits are co-expressed with them 9 . We also have recently proposed that heteromerization of TRPC4 with TRPC1 decreased the calcium rise as detected by channels tagged with GCaMP6s 36 . Here, our data showed that estimated functional PI(4,5)P 2 dissociation curves of TRPC1/4, TRPC1/5 heteromeric channels are not very different, which means that introducing TRPC1 subunits normalizes their PI(4,5)P 2 sensitivities.…”

Section: Discussionmentioning

confidence: 92%

Differential PI(4,5)P2 sensitivities of TRPC4, C5 homomeric and TRPC1/4, C1/5 heteromeric channels

Myeong

Shin

et al. 2019

Sci Rep

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Transient receptor potential canonical (TRPC) 4 and TRPC5 channels are modulated by the Gαq-PLC pathway. Since phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) maintains TRPC4 and TRPC5 channel function, the Gαq-PLC pathway inhibits channel activity by depleting PI(4,5)P2. Here we investigated the difference in PI(4,5)P2 sensitivity between homomeric and heteromeric TRPC channels. First, by using a Danio rerio voltage-sensing phosphatase (DrVSP), we show that PI(4,5)P2 dephosphorylation robustly inhibits TRPC4α, TRPC4β, and TRPC5 homotetramer currents and also TRPC1/4α, TRPC1/4β, and TRPC1/5 heterotetramer currents. Secondly, sensitivity of channels to PI(4,5)P2 dephosphorylation was suggested through the usage of FRET in combination with patch clamping. The sensitivity increased in the sequence TRPC4β < TRPC4α < TRPC5 in homotetramers, whereas when forming heterotetramers with TRPC1, the sensitivity was approximately equal between the channels. Thirdly, we determined putative PI(4,5)P2 binding sites based on a TRPC4 prediction model. By neutralization of basic residues, we identified putative PI(4,5)P2 binding sites because the mutations reduced FRET to a PI(4,5)P2 sensor and reduced the current amplitude. Therefore, one functional TRPC4 has 8 pockets with the two main binding regions; K419, K664/R511, K518, H630. We conclude that TRPC1 channel function as a regulator in setting PI(4,5)P2 affinity for TRPC4 and TRPC5 that changes PI(4,5)P2 sensitivity.

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Calcium permeability of transient receptor potential canonical (TRPC) 4 channels measured by TRPC4-GCaMP6s

Cited by 14 publications

References 39 publications

Englerin A-sensing charged residues for transient receptor potential canonical 5 channel activation

Englerin A-sensing charged residues for transient receptor potential canonical 5 channel activation

Trpm4 ion channels in pre-Bötzinger complex interneurons are essential for breathing motor pattern but not rhythm

Differential PI(4,5)P2 sensitivities of TRPC4, C5 homomeric and TRPC1/4, C1/5 heteromeric channels

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