Tetrameric Detergent‐Soluble Acetylcholinesterase from Human Caudate Nucleus: Subunit Composition and Number of Active Sites

Gennari, K; Brunner, Josef; Brodbeck, Urs

doi:10.1111/j.1471-4159.1987.tb03386.x

Cited by 78 publications

(54 citation statements)

References 47 publications

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“…3 This shows that the conclusions drawn from our studies of complexes formed in transfected COS cells are generally valid for the physiological PRiMA-anchored AChE species in mammalian brain. The present results differ from the original description of PRiMA, which was discovered as a 20-kDa protein labeled with the [ 125 I]TID hydrophobic reagent in purified preparations of membrane-bound AChE tetramers isolated from bovine brain (10,11,25). Under nonreducing conditions, this protein appeared to be disulfide-linked with two AChE T subunits forming heavy dimers, which were 20 kDa heavier than the light dimers and equally abundant.…”

Section: Abnormal Migration Of An Assembly Of Four Ache T Subunitscontrasting

confidence: 54%

“…Disulfide Bonds between AChE T Subunits and PRiMA-Previous results had suggested that, in the same manner as ColQ, PRiMA is disulfide-linked to a pair of AChE T subunits in the complex (heavy dimer), the other two being disulfide-linked to each other (light dimer) (10,11). We did observe such heavy dimers in nonreducing polyacrylamide gels, revealed either by radioactive metabolic labeling (not shown) or by Western blotting of complexes formed with constructs containing the PRAD of ColQ, such as Q N or PQ, but very little with PRiMA or with constructs containing the PRAD of PRiMA, such as P s46 or QP.…”

Section: Discussionmentioning

confidence: 99%

“…PRiMA was first discovered as a 20-kDa hydrophobic protein associated with membrane-bound AChE tetramers purified from bovine brain (10,11). This protein could be labeled with the hydrophobic reagent […”

mentioning

confidence: 99%

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Acetylcholinesterase Associates Differently with Its Anchoring Proteins ColQ and PRiMA

Noureddine

Carvalho

Schmitt

et al. 2008

Journal of Biological Chemistry

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Acetylcholinesterase tetramers are inserted in the basal lamina of neuromuscular junctions or anchored in cell membranes through the interaction of four C-terminal t peptides with proline-rich attachment domains (PRADs) of cholinesterase-associated collagen Q (ColQ) or of the transmembrane protein PRiMA (proline-rich membrane anchor). ColQ and PRiMA differ in the length of their proline-rich motifs (10 and 15 residues, respectively). ColQ has two cysteines upstream of the PRAD, which are disulfide-linked to two AChE T subunits ("heavy" dimer), and the other two subunits are disulfide-linked together ("light" dimer). In contrast, PRiMA has four cysteines upstream of the PRAD. We examined whether these cysteines could be linked to AChE T subunits in complexes formed with PRiMA in transfected COS cells and in the mammalian brain. For comparison, we studied complexes formed with N-terminal fragments of ColQ, N-terminal fragments of PRiMA, and chimeras in which the upstream regions containing the cysteines were exchanged. We also compared the effect of mutations in the t peptides on their association with the two PRADs. We report that the two PRADs differ in their interaction with AChE T subunits; in complexes formed with the PRAD of PRiMA, we observed light dimers, but very few heavy dimers, even though such dimers were formed with the PQ chimera in which the N-terminal region of PRiMA was associated with the PRAD of ColQ. Complexes with PQ or with PRiMA contained heavy components, which migrated abnormally in SDS-PAGE but probably resulted from disulfide bonding of four AChE T subunits with the four upstream cysteines of the associated protein.Mammalian cholinergic tissues mostly express the T ("tailed") variant of acetylcholinesterase (AChE T ), 2 in which the C-terminal 40-residue t peptide allows the formation of AChE T tetramers, associated with the collagen ColQ and the transmembrane protein PRiMA (1, 2). Heteromeric complexes containing ColQ are attached to the basal lamina at neuromuscular junctions, whereas complexes containing PRiMA are anchored in cell membranes and represent the major AChE species in the brain (3).We have previously shown that the t peptide forms an amphiphilic ␣-helix, with a sector containing seven aromatic residues that are strictly conserved in all vertebrate cholinesterases (AChE, as well as butyryl cholinesterase (BChE)) (4). Although AChE T and other AChE variants can form dimers through an association zone located in the catalytic domain (the "four-helix bundle," formed by two helices from each subunit) and an intercatenary disulfide bond through a C-terminal cysteine (5), only AChE T subunits form tetramers and associate with anchoring proteins through an assembly of four C-terminal t peptides, also called tryptophan amphiphilic tetramerization domains. Aromatic residues play a major role in the association of four t peptides with proline-rich motifs that exist in the N-terminal regions of ColQ and PRiMA (3, 6). These motifs are sufficient for the association with t peptides, an...

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Section: Abnormal Migration Of An Assembly Of Four Ache T Subunitscontrasting

confidence: 54%

Section: Discussionmentioning

confidence: 99%

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Acetylcholinesterase Associates Differently with Its Anchoring Proteins ColQ and PRiMA

Noureddine

Carvalho

Schmitt

et al. 2008

Journal of Biological Chemistry

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“…3 This implies that the protein was transferred into the endoplasmic reticulum, where it was correctly folded and acquired intra-molecular disulfide bonds. The processing of this protein in the secretory pathway was confirmed by its N-glycosylation and secretion.…”

Section: In Mammals Cuta Produces Several Variants Differing Inmentioning

confidence: 99%

“…In these hetero-oligomers, four catalytic subunits, corresponding to the AChE T variant that possesses a C-terminal t peptide (2), are associated with a hydrophobic 20-kDa protein (3,4). This protein has now been cloned and named PRiMA (proline-rich membrane anchor) (5).…”

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confidence: 99%

Protein CutA Undergoes an Unusual Transfer into the Secretory Pathway and Affects the Folding, Oligomerization, and Secretion of Acetylcholinesterase

Liang

Nunes-Tavares

Xie

et al. 2009

Journal of Biological Chemistry

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The mammalian protein CutA was first discovered in a search for the membrane anchor of mammalian brain acetylcholinesterase (AChE). It was co-purified with AChE, but it is distinct from the real transmembrane anchor protein, PRiMA. CutA is a ubiquitous trimeric protein, homologous to the bacterial CutA1 protein that belongs to an operon involved in resistance to divalent ions ("copper tolerance A"). The function of this protein in plants and animals is unknown, and several hypotheses concerning its subcellular localization have been proposed. We analyzed the expression and the subcellular localization of mouse CutA variants, starting at three in-frame ATG codons, in transfected COS cells. We show that CutA produces 20-kDa (H) and 15-kDa (L) components. The H component is transferred into the secretory pathway and secreted, without cleavage of a signal peptide, whereas the L component is mostly cytosolic. We show that expression of the longer CutA variant reduces the level of AChE, that this effect depends on the AChE C-terminal peptides, and probably results from misfolding. Surprisingly, CutA increased the secretion of a mutant possessing a KDEL motif at its C terminus; it also increased the formation of AChE homotetramers. We found no evidence for a direct interaction between CutA and AChE. The longer CutA variant seems to affect the processing and trafficking of secretory proteins, whereas the shorter one may have a distinct function in the cytoplasm.

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Enzymes Processing Neurotransmitters

2019

Chemical Biology of Neurodegeneration

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Tetrameric Detergent‐Soluble Acetylcholinesterase from Human Caudate Nucleus: Subunit Composition and Number of Active Sites

Cited by 78 publications

References 47 publications

Acetylcholinesterase Associates Differently with Its Anchoring Proteins ColQ and PRiMA

Acetylcholinesterase Associates Differently with Its Anchoring Proteins ColQ and PRiMA

Protein CutA Undergoes an Unusual Transfer into the Secretory Pathway and Affects the Folding, Oligomerization, and Secretion of Acetylcholinesterase

Enzymes Processing Neurotransmitters

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