Involvement of Phosphatidylinositol 4,5-Bisphosphate in the Desensitization of Canonical Transient Receptor Potential 5

Kim, Byung Joo; Kim, Min Tae; Jeon, Ju Hong; Kim, Seon Jeong; So, Insuk

doi:10.1248/bpb.31.1733

Cited by 30 publications

(25 citation statements)

References 29 publications

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“…9A; a ) from that in the presence of CCK (Fig. 9A; b ) was similar to that of overexpressed TRPC5 (transient receptor potential classical 5) in HEK 293 cells [33,34]. These results suggest that TRPC5 channel is a candidate for CCK induced inward currents in cultured ICCs from murine small intestine.…”

Section: Resultssupporting

confidence: 72%

Characteristics of the Cholecystokinin-Induced Depolarization of Pacemaking Activity in Cultured Interstitial Cells of Cajal from Murine Small Intestine

Lee

Kim

Kwon

et al. 2013

Cell Physiol Biochem

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1,160

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Background/Aims: In this study, we studied the effects of cholecystokinin (CCK) on pacemaker potentials in cultured interstitial cells of Cajal (ICCs) from mouse small intestine using the whole cell patch clamp technique. Methods: ICCs are pacemaker cells that exhibit periodic spontaneous depolarization, which is responsible for the production of slow waves in gastrointestinal smooth muscle, and generate periodic pacemaker potentials in current-clamp mode. Results: Exposure to CCK (100 nM-5 µM) decreased the amplitudes of pacemaker potentials and depolarized resting membrane potentials. To identify the type of CCK receptors involved in ICCs, we examined the effects of CCK agonists and found that the addition of CCK₁ agonist (A-71323, 1 µM) depolarized resting membrane potentials, whereas exposure to CCK₂ agonist (gastrin , 1 µM) had no effect on pacemaker potentials. To confirm these results, we examined the effects of CCK antagonists and found that pretreatment with CCK₁ antagonist (SR 27897, 1 µM) blocked CCK-induced effects. However, pretreatment with CCK₂ antagonist (LY 225910, 1 µM) did not. Furthermore, intracellular GDP_βS suppressed CCK-induced effects. To investigate the involvements of phospholipase C (PLC), protein kinase C (PKC), and protein kinase A (PKA) in the effects of CCK in cultured ICCs, we used U-73122 (an active PLC inhibitor), chelerythrine (a PKC inhibitor), SQ-22536 (an inhibitor of adenylate cyclase), or mPKAI (an inhibitor of myristoylated PKA). All inhibitors blocked the CCK-mediated effects on pacemaker potentials. In addition, we found that transient receptor potential classical 5 (TRPC5) channel was involved in CCK-activated currents in cultured ICCs. Conclusion: These results suggest that the CCK induced depolarization of pacemaking activity occurs in a G-protein-, PLC-, PKC-, and PKA-dependent manner via CCK₁ receptor and TRPC5 channel is a candidate for CCK-activated currents in cultured ICCs in murine small intestine. Therefore, the ICCs are targets for CCK and their interaction can affect intestinal motility.

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Section: Resultssupporting

confidence: 72%

Characteristics of the Cholecystokinin-Induced Depolarization of Pacemaking Activity in Cultured Interstitial Cells of Cajal from Murine Small Intestine

Lee

Kim

Kwon

et al. 2013

Cell Physiol Biochem

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1,160

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“…The DAG-sensitive TRPC3/C6/C7 channels seemed to require both PIP 2 itself and its product, DAG, to maintain channel activity (46,47). Although TRPC4/C5 are not sensitive to DAG, increasing PIP 2 levels also helped sustain the activation of TRPC4β and C5 (29,48). For TRPC4, the PIP 2 dependence may be explained by the fact that membrane translocation of PLCδ1 requires this lipid (41), but this will not be applicable to TRPC5, which is not dependent on PLCδ1.…”

Section: Discussionmentioning

confidence: 99%

Critical roles of G_i/oproteins and phospholipase C-δ1 in the activation of receptor-operated TRPC4 channels

Thakur

Tian

Jeon

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Transient Receptor Potential Canonical (TRPC) proteins form nonselective cation channels commonly known to be activated downstream from receptors that signal through phospholipase C (PLC). Although TRPC3/C6/C7 can be directly activated by diacylglycerols produced by PLC breakdown of phosphatidylinositol 4,5-bisphosphate (PIP 2 ), the mechanism by which the PLC pathway activates TRPC4/C5 remains unclear. We show here that TRPC4 activation requires coincident stimulation of G i/o subgroup of G proteins and PLCδ, with a preference for PLCδ1 over PLCδ3, but not necessarily the PLCβ pathway commonly thought to be involved in receptor-operated TRPC activation. In HEK293 cells coexpressing TRPC4 and G i/o -coupled μ opioid receptor, μ agonist elicited currents biphasically, with an initial slow phase preceding a rapidly developing phase. The currents were dependent on intracellular Ca 2+ and PIP 2 . Reducing PIP 2 through phosphatases abolished the biphasic kinetics and increased the probability of channel activation by weak G i/o stimulation. In both HEK293 cells heterologously expressing TRPC4 and renal carcinoma-derived A-498 cells endogenously expressing TRPC4, channel activation was inhibited by knocking down PLCδ1 levels and almost completely eliminated by a dominant-negative PLCδ1 mutant and a constitutively active RhoA mutant. Conversely, the slow phase of G i/o -mediated TRPC4 activation was diminished by inhibiting RhoA or enhancing PLCδ function. Our data reveal an integrative mechanism of TRPC4 on detection of coincident G i/o , Ca 2+ , and PLC signaling, which is further modulated by the small GTPase RhoA. This mechanism is not shared with the closely related TRPC5, implicating unique roles of TRPC4 in signal integration in brain and other systems.Canonical TRPs (TRPC1-7) are the most homologous to the prototypical Drosophila TRP and are believed to be activated downstream of phospholipase C (PLC) (1). In both heterologous and native systems, stimulating PLCβ via the G q/11 subgroup of G proteins is commonly used to activate TRPC channels. Recent studies, however, also suggest a role for G i/o subgroup of G proteins in the activation of TRPC4/C5 (2-4).TRPC4 is implicated in the regulation of microvascular permeability (5), renal cancer proliferation (6, 7), neurotransmitter release (8), intestinal contraction and motility (9), neurite extension (10), epileptiform burst firing, and seizure-induced neurodegeneration (11). The channel mediates Na + and Ca 2+ influx, causing membrane depolarization and intracellular Ca 2+ concentration ([Ca 2+ ] i ) elevation, which in turn alter cell function (12). Although advances have been made in demonstrating TRPC4 channel activation under G i/o and/or PLC stimulation, as well as its dependence on [Ca 2+ ] i , a precise description of signaling events underlying the mechanism of TRPC4 activation remains elusive.Here, we distinguished the contributions of G q/11 and G i/o pathways to TRPC4 activation and uncovered a strict codependence on G i/o and PLC pathways. We focuse...

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“…In contrast to other TRPC channels, TRPC4 and -5 are inhibited by PIP 2 and depletion of the phospholipid results in current potentiation (11,12,43). It has been postulated that membrane-bound PIP 2 interacts with the C terminus of TRPC4α, thereby stabilizing the closed channel conformation in the presence of NHERF1 (11).…”

Section: Significancementioning

confidence: 99%

Dynamic NHERF interaction with TRPC4/5 proteins is required for channel gating by diacylglycerol

Storch

Forst

Pardatscher

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

122

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The activation mechanism of the classical transient receptor potential channels TRPC4 and -5 via the G q/11 protein-phospholipase C (PLC) signaling pathway has remained elusive so far. In contrast to all other TRPC channels, the PLC product diacylglycerol (DAG) is not sufficient for channel activation, whereas TRPC4/5 channel activity is potentiated by phosphatidylinositol 4,5-bisphosphate (PIP 2 ) depletion. As a characteristic structural feature, TRPC4/5 channels contain a C-terminal PDZ-binding motif allowing for binding of the scaffolding proteins Na+ exchanger regulatory factor (NHERF) 1 and 2. PKC inhibition or the exchange of threonine for alanine in the C-terminal PDZ-binding motif conferred DAG sensitivity to the channel. Altogether, we present a DAG-mediated activation mechanism for TRPC4/5 channels tightly regulated by NHERF1/2 interaction. PIP 2 depletion evokes a C-terminal conformational change of TRPC5 proteins leading to dynamic dissociation of NHERF1/2 from the C terminus of TRPC5 as a prerequisite for DAG sensitivity. We show that NHERF proteins are direct regulators of ion channel activity and that DAG sensitivity is a distinctive hallmark of TRPC channels.and -5 channels are members of the classical transient receptor potential cation (TRPC) family of nonselective, calcium permeable receptor-operated cation channels. They are widely expressed in many tissues, including brain, kidney, and the vascular system. High expression levels are found in the central nervous system where TRPC4 and -5 are involved in amygdala function and fear-related behavior (1, 2), seizure, and excitotoxicity (3). Furthermore, TRPC5 channels are implicated in neuronal depolarization and bursting during epiletiform seizures (4) and regulate hippocampal neurite length and growth cone morphology (5). In the kidney, TRPC5 channels are proposed to be protective against renal failure (6). TRPC channels are usually activated by G q/11 proteincoupled receptors via phospholipase C (PLC) activation resulting in cleavage of phosphatidylinositol-3,4-bisphosphate (PIP 2 ) into the second messengers inositol-1,4,5-trisphosphate (IP 3 ) and diacylglycerol (DAG). DAG is known to activate TRPC2, -3, -6, and -7 (7-9) channels, whereas TRPC4 and -5 are supposed to be insensitive to the PLC product DAG (8) and are even inhibited by DAG or its membrane-permeable analog 1-oleoyl-2-acetyl-sn-glycerol (OAG) (10). DAG-mediated TRPC5 channel inhibition was shown to be PKC dependent (10). Furthermore, TRPC4 and -5 channels can be activated by depleting PIP 2 (11, 12), contrary to TRPC6 and -7 channels, which are inhibited by PIP 2 depletion (13). However, there are first hints to show that endogenously expressed TRPC5 channels might be DAG sensitive (14) but mechanistic insight is lacking so far.A noteworthy structural difference between TRPC4 and -5 and the established DAG-sensitive TRPC3, -6, and -7 channels is the PDZbinding motif VTTLR in the C termini of TRPC4 and -5 channels (15-17) as a structural basis of the interaction with Na + /H + e...

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Involvement of Phosphatidylinositol 4,5-Bisphosphate in the Desensitization of Canonical Transient Receptor Potential 5

Cited by 30 publications

References 29 publications

Characteristics of the Cholecystokinin-Induced Depolarization of Pacemaking Activity in Cultured Interstitial Cells of Cajal from Murine Small Intestine

Characteristics of the Cholecystokinin-Induced Depolarization of Pacemaking Activity in Cultured Interstitial Cells of Cajal from Murine Small Intestine

Critical roles of G_i/oproteins and phospholipase C-δ1 in the activation of receptor-operated TRPC4 channels

Dynamic NHERF interaction with TRPC4/5 proteins is required for channel gating by diacylglycerol

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Involvement of Phosphatidylinositol 4,5-Bisphosphate in the Desensitization of Canonical Transient Receptor Potential 5

Cited by 30 publications

References 29 publications

Characteristics of the Cholecystokinin-Induced Depolarization of Pacemaking Activity in Cultured Interstitial Cells of Cajal from Murine Small Intestine

Characteristics of the Cholecystokinin-Induced Depolarization of Pacemaking Activity in Cultured Interstitial Cells of Cajal from Murine Small Intestine

Critical roles of Gi/oproteins and phospholipase C-δ1 in the activation of receptor-operated TRPC4 channels

Dynamic NHERF interaction with TRPC4/5 proteins is required for channel gating by diacylglycerol

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Critical roles of G_i/oproteins and phospholipase C-δ1 in the activation of receptor-operated TRPC4 channels