Structural basis for conductance through TRIC cation channels

@article{Su2017StructuralBF,
  title={Structural basis for conductance through TRIC cation channels},
  author={Min Su and Feng Gao and Qi Yuan and Yang Mao and De-lin Li and Youzhong Guo and Cheng Yang and Xiao-hui Wang and Renato Bruni and Brian Kloss and Hong Zhao and Yang Zeng and Faben Zhang and Andrew R. Marks and Wayne A. Hendrickson and Yu-hang Chen},
  journal={Nature Communications},
  year={2017},
  volume={8}
}
Mammalian TRICs function as K+-permeable cation channels that provide counter ions for Ca2+ handling in intracellular stores. Here we describe the structures of two prokaryotic homologues, archaeal SaTRIC and bacterial CpTRIC, showing that TRIC channels are symmetrical trimers with transmembrane pores through each protomer. Each pore holds a string of water molecules centred at kinked helices in two inverted-repeat triple-helix bundles (THBs). The pores are locked in a closed state by a… 

Structural basis for ion selectivity in TMEM175 K+ channels

The X-ray structure of a bacterial TMEM175 family member in complex with a novel chaperone built of a nanobody fusion-protein suggests major conformational rearrangements of the pore-lining helices for channel opening, possibly involving iris-like motions.

TRIC-A Channel Maintains Store Calcium Handling by Interacting With Type 2 Ryanodine Receptor in Cardiac Muscle

In addition to the ion-conducting function, TRIC-A functions as an accessory protein of RyR2 to modulate sarcoplasmic reticulum Ca2+ handling in cardiac muscle.

Structural basis for activity of TRIC counter-ion channels in calcium release

It is shown that Ca2+ binding to TRIC channels stabilizes a nonconductive conformation; however, Ca2-free TRIC, as is generated during calcium release, frees a gating residue on a voltage-sensing helix to move out of blockage in response to membrane depolarization, which can restore polarization for continued calcium release.

Enhanced activity of multiple TRIC‐B channels: an endoplasmic reticulum/sarcoplasmic reticulum mechanism to boost counterion currents

No evidence was found for a direct gating interaction between ryanodine receptor and SR K+‐channels in Tric‐a KO SR, suggesting that TRIC–B–TRIC‐B interactions are highly specific and may be important for meeting counterion requirements during excitation–contraction coupling in tissues where TRIC‐A is sparse or absent.

TRIC-A regulates intracellular Ca2+ homeostasis in cardiomyocytes

The potential roles of TRIC-A in regulating cardiac function, particularly its effects on intracellular Ca 2+ signaling of cardiomyocytes, are focused on and the current knowledge gaps are discussed.

Pseudo-Symmetric Assembly of Protodomains as a Common Denominator in the Evolution of Polytopic Helical Membrane Proteins

Interestingly, all the 6/7/8TMH pseudo-symmetric folds in this study also assemble as oligomeric forms in the membrane, emphasizing the role of symmetry in evolution, revealing self-assembly and co-evolution not only at the protodomain level but also at the domain level.

Lipid Cubic Phase for Membrane Protein X-ray Crystallography

The principles for LCP formation, membraneprotein reconstitution, and crystallization process are described and the successful application of LCP crystallization for a wide range of membrane proteins including receptors, complexes, transporters, channels, enzymes, membrane protein insertion chaperons, and outer membrane β-barrels is summarized.

7-Transmembrane Helical (7TMH) Proteins: Pseudo-Symmetry and Conformational Plasticity

The sequence/structure analysis of different 6/7/8-TMH superfamilies provides a unifying theme of their evolutionary process involving the intragenic duplication of protodomains with varying degrees of sequence and fold divergence under conformational and functional constraints.

Pseudo-Symmetry and Conformational Plasticity in 7 Transmembrane Helix (7TMH) Proteins: Intragenic Duplication and Assembly of 3TMH or 4TMH Protodomains with Evolutionary Balance of Structural Constraints and Functional Divergence

The sequence/structure analysis of different 6/7/8-TMH superfamilies provides a unifying theme of their evolutionary process involving the intragenic duplication of protodomains with varying degrees of sequence and functional divergence under structural constraints.

The functional role of Ca-and voltage-gated potassium channels in activated human T cells and fibroblast-like synoviocytes

A Debreceni Egyetem Orvostudományi Doktori Tanácsa meghívja Önt Dr. Pethő Zoltán Dénes The functional role of Ca-and voltage-gated potassium channels in activated human T cells and fibroblast-like

References

SHOWING 1-10 OF 54 REFERENCES

Crystal structures of the TRIC trimeric intracellular cation channel orthologues

The structural and functional framework for the molecular mechanism of this ion channel superfamily is provided, and it is revealed that TRIC channels possess an ion-conducting pore within each subunit, and that the trimer formation contributes to the stability of the protein.

Structural insights into Ca2+-activated long-range allosteric channel gating of RyR1

The characterization of a Ca2+-activated open-state RyR1 structure by cryo-electron microscopy provides structural insights into the molecular mechanisms of channel gating and regulation of RyRs and sheds light on structural basis for channel-gating and ion selectivity mechanisms for the six-transmembrane-helix cation channel family.

Structure of a mammalian ryanodine receptor

The closed-state structure of the 2.3-megadalton complex of the rabbit skeletal muscle type 1 RyR (RyR1), solved by single-particle electron cryomicroscopy at an overall resolution of 4.8 Å is reported.

Structure of the rabbit ryanodine receptor RyR1 at near-atomic resolution

Structural features explain high ion conductance by RyRs and the long-range allosteric regulation of channel activities and the high-conductance intracellular Ca2+ channels.

Crystal structure of the ATP-gated P2X4 ion channel in the closed state

This work defines the location of three non-canonical, intersubunit ATP-binding sites, and suggests that ATP binding promotes subunit rearrangement and ion channel opening.

The Central domain of RyR1 is the transducer for long-range allosteric gating of channel opening

Structural analyses provide important insight into the E-C coupling in skeletal muscles and identify the Central domain as the transducer that couples the conformational changes of the cytoplasmic platform to the gating of the central pore.

Bioinformatic Characterization of the Trimeric Intracellular Cation-Specific Channel Protein Family

Analysis of TRIC channels revealed that these proteins possess seven putative transmembrane segments, which arose by intragenic duplication of a three-TMS polypeptide-encoding genetic element followed by addition of a seventh TMS to give the precursor of all current TRIC family homologs.

Pore architecture of TRIC channels and insights into their gating mechanism

Structural and functional analyses unravel the central role of PIP2 in stabilizing the cytoplasmic gate of the ion permeation pathway and reveal a marked Ca2+-induced conformational change in a cytopLasmic loop above the gate.

Pore architecture and ion sites in acid sensing ion channels and P2X receptors

Comparison of the acid-sensing ion channel structure with the ATP-gated P2X4 receptor reveals similarity in pore architecture and aqueous vestibules, suggesting that there are unanticipated yet common structural and mechanistic principles.

Voltage-gated cation conductance channel from fragmented sarcoplasmic reticulum: Steady-state electrical properties

SummaryThe interaction of fragmented sarcoplasmic reticulum (SR) with an artificial planar phospholipid membrane under conditions known to induce fusion of phospholipid vesicles raises the
...