Structural determinant of TRPV1 desensitization interacts with  calmodulin

Numazaki, Mitsuko; Tominaga, Tomoko; Takeuchi, Kumiko; Murayama, Namie; Toyooka, Hidenori; Tominaga, Makoto

doi:10.1073/pnas.1337252100

Cited by 312 publications

(306 citation statements)

References 42 publications

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“…Moreover, CaM has been shown to modulate several channels from the TRP superfamily (Boulay 2002;Numazaki et al 2003;Phillips et al 1992;Singh et al 2002;Tang et al 2001;Trost et al 1999Trost et al , 2001Warr and Kelly 1996;Zhang et al 2001). TRPV5 and TRPV6 activity is negatively regulated by the intracellular Ca 2+ concentration and CaM could mediate the regulation of the activity of both channels.…”

Section: Calmodulinmentioning

confidence: 99%

The epithelial calcium channels TRPV5 and TRPV6: regulation and implications for disease

Abel

Hoenderop

Bindels

2005

Naunyn-Schmiedeberg's Arch Pharmacol

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The epithelial Ca 2+ channels TRPV5 and TRPV6 represent a new family of Ca 2+ channels that belongs to the superfamily of transient receptor potential channels. TRPV5 and TRPV6 constitute the apical Ca 2+ entry mechanism in active Ca 2+ transport in kidney and intestine. The central role of TRPV5 and TRPV6 in active Ca 2+ (re)absorption makes it a prime target for regulation to maintain Ca 2+ balance. This review covers the hormonal regulation, interaction with accessory proteins and (patho)physiological implications of these epithelial Ca 2+ channels.

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Section: Calmodulinmentioning

confidence: 99%

The epithelial calcium channels TRPV5 and TRPV6: regulation and implications for disease

Abel

Hoenderop

Bindels

2005

Naunyn-Schmiedeberg's Arch Pharmacol

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“…Among them, Ca 2+ ions are important because not only the effects are substantial and rapid but also Ca 2+ influx through activated channels provides a powerful physiological negative feedback mechanism 10 . Modulation of channel activity by intracellular Ca 2+ is mediated by multiple mechanisms utilizing calmodulin 34,35,41,42 , Phosphorylation 43 , and PIP2 [44][45][46][47][48] . As F430_3aa and E693_8aa exhibit specific and substantial deficits in Ca 2+ -dependent desensitization, they may serve as useful tools to further investigate the allosteric coupling process between the intracellular domains and the transmembrane core domain.…”

Section: Discussionmentioning

confidence: 99%

“…Extended recordings, however, revealed that there was a substantial difference in the current decline phase. The current decline represents Ca 2+ -dependent acute desensitization, a process thought to be mediated by multiple mechanisms, including binding of Ca 2+ -calmodulin to the ankyrin-like repeat domain 34,35,41,42 , phosphorylation 43 , and binding of PIP2 to the C-terminus [44][45][46][47][48] , that allosterically modulate the stability of the open pore conformation. For the wild-type channel, as expected little desensitization was observed in the absence of Ca 2+ .…”

Section: Functional Tests Of Insertion Mutantsmentioning

confidence: 99%

Exploring Functional Roles of TRPV1 Intracellular Domains with Unstructured Peptide-Insertion Screening

Yang

et al. 2017

Biophysical Journal

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TRPV1 is a polymodal nociceptor for diverse physical and chemical stimuli that interact with different parts of the channel protein. Recent cryo-EM studies revealed detailed channel structures, opening the door for mapping structural elements mediating activation by each stimulus. Towards this goal, here we have combined unstructured peptide-insertion screening (UPS) with electrophysiological and fluorescence recordings to explore structural and functional roles of the intracellular regions of TRPV1 in mediating various activation stimuli. We found that most of the tightly packed protein regions did not tolerate structural perturbation by UPS when tested, indicating that structural integrity of the intracellular region is critical. In agreement with previous reports, Ca 2+ -dependent desensitization is strongly dependent on both intracellular N-and C-terminal domains; insertions of an unstructured peptide between these domains and the transmembrane core domain nearly eliminated Ca 2+ -dependent desensitization. In contrast, channel activations by capsaicin, low pH, divalent cations, and even heat are mostly intact in mutant channels containing the same insertions. These observations suggest that the transmembrane core domain of TRPV1, but not the intracellular domains, is responsible for sensing these stimuli.TRPV1 ion channel can be directly activated or modulated by capsaicin 1 , heat 1 , extracellular proton 2 , divalent cations 3 , Na + 4 , peptide toxins from spider 5 , centipede 6 , and scorpion 7 , membrane depolarization 8 , intracellular Ca 2+ 9 , and many other factors 10 . A noticeable feature of TRPV1 polymodal activation emerging from biophysical investigations is the existence of non-overlapping activation pathways [11][12][13] . However, except for capsaicin 14-19 , proton 11,20 , and animal toxins 6,21 , the channel structures that sense activation stimuli are poorly defined. Recent cryo-EM studies revealed that the transmembrane core domain of TRPV1 resembles that of tetrameric cation channels, with six transmembrane helical segments surrounding a centrally located ion permeation pore 22,23 . The partially resolved intracellular N-and C-terminal domains contain special structures such as the ankyrin-like repeat domains and the TRP domain that likely play crucial structural and/or functional roles 10 . Arrangement of intracellular domains has been investigated using fluorescence resonance energy transfer 24 . A major task for TRPV1 study in the post-structure era is to assign functional roles to individual structure domains.The unstructured peptide-insertion screening (UPS) strategy had been used to rapidly and reliably obtain information on structure-function relationships in an ion channel even before detailed protein structures were available. In one effective application, isolating the pore domain of yeast TRPY1 channel from the intracellular Ca 2+ -sensing domain with unstructured peptides demonstrated that the pore domain was mechanosensitive 25 . Similarly, unstructured peptide insertion...

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“…5C, red arrow), which would potentially orient it where it could easily form either intra-or intersubunit AID complexes to prevent channel opening. The most well characterized effect of Ca 2+ -CaM on TrpV1 is desensitization (24), but this function is thought to primarily occur through binding to a lower-affinity site in the ARD of the N terminus (6,25). Curiously, mutations which prevent CaM binding to this C-terminal CBD in fact have subdued peak current densities (ref.…”

Section: Discussionmentioning

confidence: 99%

A channelopathy mechanism revealed by direct calmodulin activation of TrpV4

Loukin

Teng

Kung

2015

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

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Ca 2+ -calmodulin (CaM) regulates varieties of ion channels, including Transient Receptor Potential vanilloid subtype 4 (TrpV4). It has previously been proposed that internal Ca 2+ increases TrpV4 activity through Ca 2+ -CaM binding to a C-terminal Ca 2+ -CaM binding domain (CBD). We confirmed this model by directly presenting Ca 2+ -CaM protein to membrane patches excised from TrpV4-expressing oocytes. Over 50 TRPV4 mutations are now known to cause heritable skeletal dysplasia (SD) and other diseases in human. We have previously examined 14 SD alleles and found them to all have gain-of-function effects, with the gain of constitutive open probability paralleling disease severity. Among the 14 SD alleles examined, E797K and P799L are located immediate upstream of the CBD. They not only have increase basal activity, but, unlike the wild-type or other SD-mutant channels examined, they were greatly reduced in their response to Ca 2+ -CaM. Deleting a 10-residue upstream peptide (Δ795-804) that covers the two SD mutant sites resulted in strong constitutive activity and the complete lack of Ca 2+ -CaM response. We propose that the region immediately upstream of CBD is an autoinhibitory domain that maintains the closed state through electrostatic interactions, and adjacent detachable Ca 2+ -CaM binding to CBD sterically interferes with this autoinhibition. This work further supports the notion that TrpV4 mutations cause SD by constitutive leakage. However, the closed conformation is likely destabilized by various mutations by different mechanisms, including the permanent removal of an autoinhibition documented here.skeletal dysplasia | calcium | ion channel | autoinhibition | TrpV1

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Structural determinant of TRPV1 desensitization interacts with calmodulin

Cited by 312 publications

References 42 publications

The epithelial calcium channels TRPV5 and TRPV6: regulation and implications for disease

The epithelial calcium channels TRPV5 and TRPV6: regulation and implications for disease

Exploring Functional Roles of TRPV1 Intracellular Domains with Unstructured Peptide-Insertion Screening

A channelopathy mechanism revealed by direct calmodulin activation of TrpV4

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