Cytoplasmic regions adjacent to the M3 and M4 transmembrane segments influence expression and function of α7 nicotinic acetylcholine receptors. A study with single amino acid mutants

Castelán, Francisco; Mulet, José; Aldea, Marcos; Sala, Salvador; Sala, Francisco; Criado, Manuel

doi:10.1111/j.1471-4159.2006.04202.x

Cited by 15 publications

(19 citation statements)

References 30 publications

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“…The truncation of the Pxα6 coding sequence after exon 9 in the mutant may indicate that spinosad is interacting with the wild type nAChR molecule at the intracellular receptor loop between TM3 and TM4, which is removed by this truncation. These loops are thought to be involved with receptor biosynthesis and assembly, and can affects the rate at which current flows through the receptor's channel [45]. Alternatively, spinosad may interact with the extracellular carboxy-terminus of the protein, although this seems unlikely as only 8 amino acids are predicted outside the membrane.…”

Section: Discussionmentioning

confidence: 99%

Mis-Spliced Transcripts of Nicotinic Acetylcholine Receptor α6 Are Associated with Field Evolved Spinosad Resistance in Plutella xylostella (L.)

et al. 2010

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The evolution of insecticide resistance is a global constraint to agricultural production. Spinosad is a new, low-environmental-risk insecticide that primarily targets nicotinic acetylcholine receptors (nAChR) and is effective against a wide range of pest species. However, after only a few years of application, field evolved resistance emerged in the diamondback moth, Plutella xylostella, an important pest of brassica crops worldwide. Spinosad resistance in a Hawaiian population results from a single incompletely recessive and autosomal gene, and here we use AFLP linkage mapping to identify the chromosome controlling resistance in a backcross family. Recombinational mapping with more than 700 backcross progeny positioned a putative spinosad target, nAChR alpha 6 (Pxα6), at the resistance locus, PxSpinR. A mutation within the ninth intron splice junction of Pxα6 results in mis-splicing of transcripts, which produce a predicted protein truncated between the third and fourth transmembrane domains. Additional resistance-associated Pxα6 transcripts that excluded the mutation containing exon were detected, and these were also predicted to produce truncated proteins. Identification of the locus of resistance in this important crop pest will facilitate field monitoring of the spread of resistance and offer insights into the genetic basis of spinosad resistance in other species.

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Section: Discussionmentioning

confidence: 99%

Mis-Spliced Transcripts of Nicotinic Acetylcholine Receptor α6 Are Associated with Field Evolved Spinosad Resistance in Plutella xylostella (L.)

et al. 2010

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“…These observations suggest that the importance of the interaction between the N-terminal α helix and MIR loop, for conformational maturation and assembly, which we have demonstrated in α1/α7 chimeras, is a general phenomenon applying to all subunits of AChRs and related receptors. Transmembrane domain interactions and cytoplasmic regions adjacent to the transmembrane domains can also influence expression and function of α7 AChRs (Gee et al, 2007; Castelan et al, 2007). …”

Section: Discussionmentioning

confidence: 99%

Main Immunogenic Region Structure Promotes Binding of Conformation-Dependent Myasthenia Gravis Autoantibodies, Nicotinic Acetylcholine Receptor Conformation Maturation, and Agonist Sensitivity

Luo¹,

Taylor²,

Losen³

et al. 2009

J. Neurosci.

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The main immunogenic region (MIR) is a conformation-dependent region at the extracellular apex of ␣1 subunits of muscle nicotinic acetylcholine receptor (AChR) that is the target of half or more of the autoantibodies to muscle AChRs in human myasthenia gravis and rat experimental autoimmune myasthenia gravis. By making chimeras of human ␣1 subunits with ␣7 subunits, both MIR epitopes recognized by rat mAbs and by the patient-derived human mAb 637 to the MIR were determined to consist of two discontiguous sequences, which are adjacent only in the native conformation. The MIR, including loop ␣1 67-76 in combination with the N-terminal ␣ helix ␣1 1-14, conferred high-affinity binding for most rat mAbs to the MIR. However, an additional sequence corresponding to ␣1 15-32 was required for high-affinity binding of human mAb 637. A water soluble chimera of Aplysia acetylcholine binding protein with the same ␣1 MIR sequences substituted was recognized by a majority of human, feline, and canine myasthenia gravis sera. The presence of the ␣1 MIR sequences in ␣1/␣7 chimeras greatly promoted AChR expression and significantly altered the sensitivity to activation. This reveals a structural and functional, as well as antigenic, significance of the MIR.

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“…The large cytoplasmic domain is critical for expression of functional α7 AChRs (Valor et al. 2002; Castelan et al. 2007).…”

mentioning

confidence: 99%

“…The importance of the cytoplasmic domain for the assembly of functional α7 AChR has been revealed by mutational analysis (Castelan et al. 2007).…”

mentioning

confidence: 99%

Mutations of cytosolic loop residues impair assembly and maturation of α7 nicotinic acetylcholine receptors

Mukherjee¹,

Kuryatov²,

Moss³

et al. 2009

Journal of Neurochemistry

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Mechanisms that regulate early events in the biogenesis of the α7 nicotinic acetylcholine receptor (α7 AChR) are not well understood. Data presented here show that single amino acid mutations in the cytoplasmic loop of the α7 AChR, between position 335 and 343, abolish or attenuate expression of mature pentameric α7 AChRs in both human embryonic kidney tsA201 (HEK) and neuronal SH‐SY5Y cells. Although the number of mature α7 AChRs is increased significantly in the presence of the chaperone protein resistant to inhibitors of cholineesterase‐3 in HEK cells, sucrose gradient sedimentation reveals that the vast majority of α7 subunits are aggregated or improperly assembled. Transfection of α7 AChRs in SH‐SY5Y cells, which endogenously express the α7 AChR, results in a much larger fraction of subunits assembled into mature AChRs. Thus, efficient assembly of α7 AChRs is influenced by several regions of the large cytoplasmic domain, as well perhaps by other parts of its structure, and requires as yet unknown factors not required by other AChR subtypes.

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Cytoplasmic regions adjacent to the M3 and M4 transmembrane segments influence expression and function of α7 nicotinic acetylcholine receptors. A study with single amino acid mutants

Cited by 15 publications

References 30 publications

Mis-Spliced Transcripts of Nicotinic Acetylcholine Receptor α6 Are Associated with Field Evolved Spinosad Resistance in Plutella xylostella (L.)

Mis-Spliced Transcripts of Nicotinic Acetylcholine Receptor α6 Are Associated with Field Evolved Spinosad Resistance in Plutella xylostella (L.)

Main Immunogenic Region Structure Promotes Binding of Conformation-Dependent Myasthenia Gravis Autoantibodies, Nicotinic Acetylcholine Receptor Conformation Maturation, and Agonist Sensitivity

Mutations of cytosolic loop residues impair assembly and maturation of α7 nicotinic acetylcholine receptors

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