Structural insights and functional implications of choline acetyltransferase

Govindasamy, Lakshmanan; Pedersen, Brenda; Lian, Wei; Kukar, Thomas; Gu, Yunrong; Jin, Song; Agbandje‐McKenna, Mavis; Wu, Donghai; McKenna, Robert

doi:10.1016/j.jsb.2004.06.005

Cited by 32 publications

(34 citation statements)

References 48 publications

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“…Moreover, the functional role of pChAT-expressing DRG neurons is unclear. Because pChAT lacks a serial sequence corresponding to coding exons 6-9, including a sequence that is essential for ChAT activity (Govindasamy et al, 2004), its ability to produce ACh and to be a marker of cholinergic activity has been questioned. Even though data obtained from rat DRG suggest that pChAT is capable of ChAT activity and ACh synthesis (Bellier and Kimura, 2007), the ability of pChAT neurons to take up choline, package ACh into synaptic vesicles, and release ACh from their axon terminals remains to be demonstrated.…”

Section: Dorsal Horn Cholinergic Interneurons: Morphological Neurochmentioning

confidence: 99%

Morphological and functional characterization of cholinergic interneurons in the dorsal horn of the mouse spinal cord

Mesnage

Gaillard

Godin

et al. 2011

J of Comparative Neurology

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Endogenous acetylcholine is an important modulator of sensory processing, especially at the spinal level, where nociceptive (pain-related) stimuli enter the central nervous system and are integrated before being relayed to the brain. To decipher the organization of the local cholinergic circuitry in the spinal dorsal horn, we used transgenic mice expressing enchanced green fluorescent protein specifically in cholinergic neurons (ChAT::EGFP) and characterized the morphology, neurochemistry, and firing properties of the sparse population of cholinergic interneurons in this area. Three-dimensional reconstruction of lamina III ChAT::EGFP neurons based either on their intrinsic fluorescence or on intracellular labeling in live tissue demonstrated that these neurons have long and thin processes that grow preferentially in the dorsal direction. Their dendrites and axon are highly elongated in the rostrocaudal direction, beyond the limits of a single spinal segment. These unique morphological features suggest that dorsal horn cholinergic interneurons are the main contributors to the plexus of cholinergic processes located in lamina IIi, just dorsal to their cell bodies. In addition, immunostainings demonstrated that dorsal horn cholinergic interneurons in the mouse are γ-aminobutyric acidergic and express nitric oxide synthase, as in rats. Finally, electrophysiological recordings from these neurons in spinal cord slices demonstrate that two-thirds of them have a repetitive spiking pattern with frequent rebound spikes following hyperpolarization. Altogether our results indicate that, although they are rare, the morphological and functional features of cholinergic neurons enable them to collect segmental information in superficial layers of the dorsal horn and to modulate it over several segments.

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Section: Dorsal Horn Cholinergic Interneurons: Morphological Neurochmentioning

confidence: 99%

Morphological and functional characterization of cholinergic interneurons in the dorsal horn of the mouse spinal cord

Mesnage

Gaillard

Godin

et al. 2011

J of Comparative Neurology

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“…The CPT-Is contain an N-terminal extension of about 140 residues that are important for attachment to the mitochondrial membrane and other functions. We and others have reported the crystal structures of CrAT (16 -21), CrOT (22), CPT-II (23,24), and the related enzyme choline acetyltransferase (25,26). The structures can be divided into two domains, N and C domains ( Fig.…”

mentioning

confidence: 99%

Crystal Structures of Murine Carnitine Acetyltransferase in Ternary Complexes with Its Substrates

Hsiao

Jogl²,

Tong

2006

Journal of Biological Chemistry

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Carnitine acyltransferases catalyze the reversible exchange of acyl groups between coenzyme A (CoA) and carnitine. They have important roles in many cellular processes, especially the oxidation of long-chain fatty acids in the mitochondria for energy production, and are attractive targets for drug discovery against diabetes and obesity. To help define in molecular detail the catalytic mechanism of these enzymes, we report here the high resolution crystal structure of wild-type murine carnitine acetyltransferase (CrAT) in a ternary complex with its substrates acetyl-CoA and carnitine, and the structure of the S554A/M564G double mutant in a ternary complex with the substrates CoA and hexanoylcarnitine. Detailed analyses suggest that these structures may be good mimics for the Michaelis complexes for the forward and reverse reactions of the enzyme, representing the first time that such complexes of CrAT have been studied in molecular detail. The structural information provides significant new insights into the catalytic mechanism of CrAT and possibly carnitine acyltransferases in general.

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“…The similar arrangement of these critical residues in IcaC of S. capitis, including the close proximity of a critical Arg80 to Phe85 and Pro87, suggested that the three residues may be involved in forming one of the active sites. The conserved histidine residue His23 in S. capitis, highlighted in the alignment, is likely to be responsible for the deprotonation of the substrates as observed in other acetyltransferases (Wu et al, 2003;Govindasamy et al, 2004;Lee et al, 2009). …”

Section: B Cui and Othersmentioning

confidence: 97%

Effects of erythromycin on the phenotypic and genotypic biofilm expression in two clinical Staphylococcus capitis subspecies and a functional analysis of Ica proteins in S. capitis

Cui

Smooker

Rouch

et al. 2015

Journal of Medical Microbiology

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The ica operon encoding polysaccharide intercellular adhesion, which facilitates biofilm formation in staphylococci, has been extensively studied in Staphylococcus epidermidis and Staphylococcus aureus. Based on in silico analysis, we suggest the following functional model for Ica proteins in S. capitis. IcaA is responsible for polysaccharide synthesis. IcaA and IcaD complete transferring the growing sugar chain to the cell surface; IcaB is a deacetylase, with the same function as IcaB of S. epidermidis. IcaC mainly modifies the synthesized glucan by acetylation. We also examined the effects of subinhibitory concentrations of erythromycin on phenotypic biofilm expression and transcription of biofilm-related genes, using isolates representing the two subspecies of Staphylococcus capitis and different biofilm and resistance phenotypes. On induction with erythromycin, biofilm density was strongly elevated in two erythromycin-resistant S. capitis, but not in three susceptible isolates. In the representative erythromycin-resistant S. capitis subsp. urealyticus, there were significant upregulations of the icaA gene and its positive regulator sarA on transition to the stationary phase without erythromycin induction. There were also significant increases in the transcription levels of icaA, rsbU and sigB corresponding to a very strong biofilm phenotype in the stationary phase on erythromycin stress. In contrast, the representative erythromycin-susceptible S. capitis subsp. capitis displayed upregulation only of altE on entry into the stationary phase with erythromycin induction, but this change was not associated with enhancement of biofilm production. These findings suggest that the two subspecies of S. capitis adopt different pathogenesis and survival strategies to adapt to a hostile environment.

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Structural insights and functional implications of choline acetyltransferase

Cited by 32 publications

References 48 publications

Morphological and functional characterization of cholinergic interneurons in the dorsal horn of the mouse spinal cord

Morphological and functional characterization of cholinergic interneurons in the dorsal horn of the mouse spinal cord

Crystal Structures of Murine Carnitine Acetyltransferase in Ternary Complexes with Its Substrates

Effects of erythromycin on the phenotypic and genotypic biofilm expression in two clinical Staphylococcus capitis subspecies and a functional analysis of Ica proteins in S. capitis

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