Neuronal Specificity of Subtype SQSC1 of Squid Putative Sodium Channel

Sato, Chikara; Hirota, Kiyonori; Matsumoto, Gen

doi:10.1006/bbrc.1995.1115

Cited by 3 publications

(2 citation statements)

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“…In a later study, this same group, using Northern blots, mapped the expression of SQSC1 in a variety of tissues. SQSC1 was widely expressed in nervous tissue, including the stellate ganglion [81]. It was not determined, however, whether it is specifically expressed in GFL neurons themselves.…”

Section: Molecular Studiesmentioning

confidence: 99%

Identified Ion Channels in the Squid Nervous System

Rosenthal

Gilly²

2003

Neurosignals

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Our modern understanding of channels as discrete voltage-sensitive and ion-selective entities comes largely from a series of classical studies using the squid giant axon. This system has also been critical for understanding how transporters and synaptic transmission operate. This review outlines attempts to assign molecular identities to the extensively studied physiological properties of this system. As it turns out, this is no simple task. Molecular candidates for voltage-gated Na⁺, K⁺, and Ca²⁺ channels, as well as ion transporters have been isolated from the squid nervous system. Both physiological and molecular approaches have been used to equate these cloned gene products with their native counterparts. In the case of the delayed rectifier K⁺ conductance, the most thoroughly studied example, two major issues further complicate the equation. First, the ability of K⁺ channel monomers to form heteromultimers with unique properties must be considered. Second, squid K⁺ channel mRNAs are extensively edited, a process that can generate a wide variety of channel proteins from a common gene. The giant axon system is beginning to play an important role in understanding the biological relevance of this latter process.

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Section: Molecular Studiesmentioning

confidence: 99%

Identified Ion Channels in the Squid Nervous System

Rosenthal

Gilly²

2003

Neurosignals

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“…In contrast, TuNa2 is distantly related to vertebrate sodium channels. Rather, TuNa2 shares unusual primary structural characteristics with invertebrate putative NaVs from squid (33), Drosophila (DSC1) (34) and sea anemone (35). These three channels have glutamic acid (E) instead of lysine (K) at the critical site for ionic selectivity in the P-region of repeat III.…”

Section: Figmentioning

confidence: 99%

Diversity of Voltage-Gated Sodium Channels in the Ascidian Larval Nervous System

Nagahora

Okada

Yahagi

et al. 2000

Biochemical and Biophysical Research Communications

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Sodium channel functioning based on an octagonal structure model

Sato¹,

Matsumoto²

1995

J. Membarin Biol.

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The complete amino acid sequence of a sodium channel from squid Loligo bleekeri has been deduced by cloning and sequence analysis of the complementary DNA. A unique feature of the squid sodium channel is the 1,522 residue sequence, approximately three-fourths of those of the rat sodium channels I, II and III. On the basis of the sequence, and in comparison with those of vertebrate sodium channels, we have proposed a tertiary structure model of the sodium channel where the transmembrane segments are octagonally aligned and the four linkers of S5-6 between segments S5 and S6 play a crucial role in the activation gate, voltage sensor and ion selective pore, which can slide, depending on membrane potentials, along inner walls consisting of alternating segments S2 and S4. The proposed octagonal structure model is contrasted with that of Noda et al. (Nature 320; 188-192, 1986). The octagonal structure model can explain the gating of activation and inactivation, and ion selectivity, as well as the action mechanism of both tetrodotoxin (TTX) and alpha-scorpion toxin (ScTX), and can be applied not only to the sodium channel, but also to the calcium channel, potassium channel and cGMP-gated channel.

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Neuronal Specificity of Subtype SQSC1 of Squid Putative Sodium Channel

Cited by 3 publications

References 0 publications

Identified Ion Channels in the Squid Nervous System

Identified Ion Channels in the Squid Nervous System

Diversity of Voltage-Gated Sodium Channels in the Ascidian Larval Nervous System

Sodium channel functioning based on an octagonal structure model

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