action potential propagation / detection of mechanical stimulus involved in sensory perception / cardiac muscle cell action potential involved in contraction / node of Ranvier / voltage-gated sodium channel complex / Interaction between L1 and Ankyrins / voltage-gated sodium channel activity / Phase 0 - rapid depolarisation / detection of temperature stimulus involved in sensory perception of pain / behavioral response to pain ...action potential propagation / detection of mechanical stimulus involved in sensory perception / cardiac muscle cell action potential involved in contraction / node of Ranvier / voltage-gated sodium channel complex / Interaction between L1 and Ankyrins / voltage-gated sodium channel activity / Phase 0 - rapid depolarisation / detection of temperature stimulus involved in sensory perception of pain / behavioral response to pain / neuronal action potential / axon terminus / sensory perception of pain / sodium ion transmembrane transport / post-embryonic development / circadian rhythm / response to toxic substance / Sensory perception of sweet, bitter, and umami (glutamate) taste / inflammatory response / axon / plasma membrane 類似検索 - 分子機能
Voltage-gated Na+ ion channel, cytoplasmic domain / Cytoplasmic domain of voltage-gated Na+ ion channel / Sodium ion transport-associated / Voltage-gated sodium channel alpha subunit, inactivation gate / Sodium ion transport-associated / SCN5A-like, C-terminal IQ motif / Voltage gated sodium channel, alpha subunit / Voltage-gated cation channel calcium and sodium / Short calmodulin-binding motif containing conserved Ile and Gln residues. / IQ motif, EF-hand binding site ...Voltage-gated Na+ ion channel, cytoplasmic domain / Cytoplasmic domain of voltage-gated Na+ ion channel / Sodium ion transport-associated / Voltage-gated sodium channel alpha subunit, inactivation gate / Sodium ion transport-associated / SCN5A-like, C-terminal IQ motif / Voltage gated sodium channel, alpha subunit / Voltage-gated cation channel calcium and sodium / Short calmodulin-binding motif containing conserved Ile and Gln residues. / IQ motif, EF-hand binding site / Voltage-dependent channel domain superfamily / Ion transport domain / Ion transport protein 類似検索 - ドメイン・相同性
Sodium channel protein type 9 subunit alpha 類似検索 - 構成要素
National Natural Science Foundation of China (NSFC)
32330052
中国
引用
ジャーナル: Proc Natl Acad Sci U S A / 年: 2025 タイトル: Critical role of extracellular loops in differential modulations of TTX-sensitive and TTX-resistant Na channels. 著者: Tong Wu / Xinyu Yang / Xueqin Jin / Nieng Yan / Zhangqiang Li / 要旨: The cardiac voltage-gated sodium channel Na1.5 is resistant to tetrodotoxin (TTXr). Here, we report a cryo-electron microscopy (cryo-EM) structure of wild-type human Na1.5, coexpressed with the β1 ...The cardiac voltage-gated sodium channel Na1.5 is resistant to tetrodotoxin (TTXr). Here, we report a cryo-electron microscopy (cryo-EM) structure of wild-type human Na1.5, coexpressed with the β1 auxiliary subunit and treated with high-concentration TTX, at 3.4 Å resolution. Structural comparison reveals the molecular determinants for the distinct responses to TTX as well as β subunits between TTXr and TTX-sensitive (TTXs) Na channels. A conserved cation-π interaction between the guanidinium group of TTX and Tyr or Phe on the P2 helix in TTXs Na channels is lost in all TTXr subtypes owing to the replacement by Cys/Ser at the corresponding locus, explaining their differential TTX sensitivities. The β1 subunit is invisible in the EM map. Comparison of Na1.5 with Na1.7 and Na1.8, which are, respectively, TTXs and TTXr, identifies four sites on the extracellular loops (ECLs) that may account for their different β1-binding abilities. When the corresponding residues in TTXs Na1.7 are replaced with those from Na1.5, the modulatory effects of β1 on channel activation and inactivation are diminished. Consistently, β1 is absent in the 3D EM reconstruction of this Na1.7 mutant. Together with our previous structure-guided discovery that TTXr channels lack a Cys on the ECL for disulfide bond formation with β2 or β4, the structure-function relationship studies underscore the importance of the ECLs in the mechanistic distinctions between TTXs and TTXr Na channels. The ECLs may be further explored for the development of subtype-specific drugs.