Disease relevance of CHAT

• Positive ChAT immunoreactivity was also demonstrated in monolayer cultures of human umbilical vein EC (HUVEC) and a human angiosarcoma EC line (HAEND) [1].
• In the present study, we demonstrate that short term exposure of IMR32 neuroblastoma cells expressing human choline acetyltransferase to A beta-(1-42) changes phosphorylation of the enzyme, resulting in increased activity and alterations in its interaction with other cellular proteins [2].
• Arg-442 is mutated spontaneously (R442H) in congenital myasthenic syndrome, rendering ChAT inactive and causing neuromuscular failure [3].
• Non-phosphorylated wild-type choline acetyltransferase expressed in Escherichia coli yielded six (69 kDa) and four isoforms (82 kDa) respectively [4].
• In this study, recombinant choline acetyltransferase from baculovirus and bacterial expression systems was used to identify protein isoforms by two-dimensional SDS/PAGE and as substrate for protein kinases [4].

Psychiatry related information on CHAT

• Preservation of nucleus basalis neurons containing choline acetyltransferase and the vesicular acetylcholine transporter in the elderly with mild cognitive impairment and early Alzheimer's disease [5].
• Choline acetyltransferase (ChAT) activity was analyzed in reticular (Re), mediodorsal (MD) and centromedian (CM) thalamic nuclei in series of nine controls, five DLB with parkinsonism (DLB + P), five DLB without parkinsonism (DLB - P), six PD without dementia and 14 PDD cases [6].
• Choline acetyltransferase activity and vesamicol binding in Rett syndrome and in rats with nucleus basalis lesions [7].
• In Brodmann area 36, DELs were significantly associated with elevated pirenzepine binding (131.0 vs 93.5, t = 2.7), whereas visual hallucinations were associated with significant reductions in ChAT (1.7 vs 2.5, t = 2.5) [8].
• Dopamine, noradrenaline, glutamic acid decarboxylase and choline acetyltransferase were measured in various regions of brain obtained at autopsy from a large series of cases of Huntington's chorea, dying with advanced forms of the disease [9].

High impact information on CHAT

• Similarly, the activity of choline acetyltransferase and the levels of gamma-aminobutyric acid and glutamic acid in the cerebral cortex and basal ganglia were within the control range [10].
• Serotonin and 5-hydroxyindoleacetic acid levels were increased, striatal choline acetyltransferase levels were low, and striatal glutamic acid decarboxylase and guanylate cyclase activities were unaltered [11].
• In addition, the samples were assayed for the gamma-aminobutyric-acid-synthesizing enzyme, glutamic acid decarboxylase, and for the acetylcholine-synthesizing enzyme, choline acetyltransferase [12].
• That the SCN contains a cholinergic marker like ChAT and is responsive to cholinergic agents but does not bind nicotine or ACh reflects a general problem in reconciling functional, physiological, and anatomical markers of neurotransmission [13].
• Dysfunction and death of basal forebrain cholinergic neurones projecting to forebrain targets are associated with marked decreases in cholinergic markers, including the activity of choline acetyltransferase (ChAT) [14].

Chemical compound and disease context of CHAT

• Choline acetyltransferase (ChAT) is the key enzyme responsible for the synthesis of the neurotransmitter acetylcholine and is reduced in various central neurodegenerative diseases [15].
• VIP-sensitive adenylate cyclase, guanylate cyclase, muscarinic receptors, choline acetyltransferase and acetylcholinesterase, in brain tissue afflicted by Alzheimer's disease/senile dementia of the Alzheimer type [16].
• To overcome this problem, brain regions from patients with or without Alzheimer's disease were frozen within 4 h of death and examined for both choline acetyltransferase activity and for binding of [3H]-hemicholinium-3 to the choline transporter [17].
• Arginine vasopressin and choline acetyltransferase in brains of patients with Alzheimer type senile dementia [18].
• In dementia alone a selective loss was found of somatostatin content of the superior parietal lobule and of serotonin 1A sites and choline acetyltransferase activity in all areas examined [19].

Biological context of CHAT

• Vertebrate ChAT mRNAs can contain one or more of three non-coding exons, M, N or R and by RT-PCR we demonstrate, at least, a chicken ChAT mRNA containing exon M [20].
• Here, we present recent neuroanatomical, developmental, and evolutionary insights into the chemical coding of cholinergic neurotransmission that have been gleaned from the study of the CGL, and its protein products VAChT and ChAT, which comprise a synthesis-sequestration pathway that functionally defines the cholinergic phenotype [21].
• The cholinergic gene locus (CGL) was first identified in 1994 as the site (human chromosome 10q11.2) at which choline acetyltransferase and a functional vesicular acetylcholine transporter are co-localized [21].
• The first intron of the ChAT gene encompasses the open reading frame encoding another protein, vesicular acetylcholine transporter (VAChT), which is responsible for the transportation of acetylcholine from the cytoplasm into the synaptic vesicles [22].
• These data suggest that 69-kDa choline acetyltransferase is a nucleocytoplasmic shuttling protein with a predominantly cytoplasmic localization determined by a functional nuclear localization signal and unidentified putative nuclear export signal [23].

Anatomical context of CHAT

• NOS-immunoreactive motor neurons projected for longer distances than those with ChAT immunoreactivity and were larger [24].
• In the placenta, stromal fibroblasts, endothelial cells, and trophoblastic cells of the chorionic villi were positively stained with anti-ChAT antibody but not with anti-VAChT antibody [25].
• Western blot analyses showed normal levels of VAChT immunoreactivity in hippocampus of all drug user groups, whereas in the dopamine-rich caudate VAChT levels were selectively elevated (+48%) in the methamphetamine group, including the three high-dose methamphetamine users who had severely reduced ChAT activity [26].
• Antisera raised against the RNA-binding protein Hu, were used to identify nerve cell bodies in whole mounts of the myenteric plexus of human colon, and then were utilized to analyse cells immunoreactive for combinations of choline acetyltransferase and nitric oxide synthase [27].
• Multiple ChAT mRNA species (R-, N0-, N1-, N2-, and M-types) having an identical coding region and different 5'-noncoding regions have been discovered in human brain and spinal cord [28].

Associations of CHAT with chemical compounds

• The proportions of neurones containing ChAT and SP were significantly higher in inflamed (11.8%) and non-inflamed (13.9%) areas than in controls (5.0%) [29].
• The enzyme choline acetyltransferase [EC 2.3.1.6] (ChAT) synthesizes the neurotransmitter acetylcholine that plays a key morphogenic role in vertebrate retina development [20].
• To the extent that cholinergic neuron integrity can be inferred from VAChT concentration, our data suggest that methamphetamine does not cause loss of striatal cholinergic neurons, but might damage/downregulate brain ChAT in some high-dose users [26].
• However, both ACh and mRNA for ChAT are expressed in mononuclear leukocytes and various human leukemic T-cell lines [28].
• Thus, in HUVEC cultures, ChAT activity amounted to 0.78 +/- 0.15 nmol x mg protein(-1) x h(-1) (n = 3), but was only partially (about 50%) inhibited by the ChAT inhibitor bromoacetylcholine (30 microM) [1].

Physical interactions of CHAT

• In the medial occipital gyrus, galanin binding in the AD cases was not different from controls in any cortical layer despite a reduction in choline acetyltransferase activity [30].
• Single- and double-immunostaining procedures were used to study the distribution of the acetylcholine synthesizing enzyme choline acetyltransferase (ChAT) and the calcium binding protein calbindin D-28k in the nucleus basalis of Meynert (nbM) and in the pedunculopontine nucleus (PPN) of the squirrel monkey (Saimiri sciureus) [31].

Co-localisations of CHAT

• PACAP was found to be co-localized with ChAT in nerve fibers of the intraganglionic spiral bundle and beneath the inner and outer hair cells within the organ of Corti [32].
• Virtually all (greater than 90%) NGF receptor-containing neurons co-localize with the specific cholinergic marker choline acetyltransferase (ChAT) within the nucleus basalis in PD [33].

Regulatory relationships of CHAT

• Treatment with dbcAMP plus dexamethasone resulted in the largest increase of VAChT mRNA amount while retinoic acid mostly enhanced ChAT mRNA level [34].
• Moreover, cotreatment with bFGF reduced the ability of CNTF to enhance choline acetyltransferase [35].
• Polysialic acid limits choline acetyltransferase activity induced by brain-derived neurotrophic factor [36].
• We previously described that the major promoter (M) of human choline acetyltransferase (ChAT) gene is activated by three inhibitors of histone deacetylase, butyrate, trichostatin and trapoxin, in transfected CHP126 neuroepithelioma cells [37].
• Cultures grown in IGF II- or nerve growth factor-containing medium expressed increased choline acetyltransferase activity [38].

Other interactions of CHAT

• Correlation of vasoactive intestinal peptide and nitric oxide synthase with choline acetyltransferase in the airway innervation [39].
• Phosphorylation of 69-kDa choline acetyltransferase at threonine 456 in response to amyloid-beta peptide 1-42 [2].
• Whereas phosphorylation of choline acetyltransferase by protein kinase C alone caused a 2-fold increase in enzyme activity, phosphorylation by CaM kinase II alone did not alter enzyme activity [2].
• By using polymerase chain reaction, single stranded conformation polymorphism or the LightCycler analysis we detected a single nucleotide polymorphism in the first common coding exon of the ChAT gene [40].
• In the commissural part of the nucleus tractus solitarius, no alpha-MSH-containing cell bodies were found to have ChAT or VAChT immunoreactivity [41].

Analytical, diagnostic and therapeutic context of CHAT

• Light and electron microscopic visualization of VAChT, complementing previous ChAT immunohistochemistry, has improved understanding of the genesis and function of the cholinergic vesicle, neuron, and synapse [42].
• In tissue sections of human skin, immunohistochemical studies using confocal laser scanning microscopy showed ChAT (choline acetyltransferase) activity in the EC of dermal blood vessels [1].
• Localization of a 900-bp-long fragment of the human choline acetyltransferase gene to 10q11.2 by nonradioactive in situ hybridization [43].
• A DNA fragment of 219 bp was obtained by polymerase chain reaction (PCR) on human genomic DNA using two oligonucleotide mixtures derived from peptide sequences of human placenta choline acetyltransferase (ChAT) and from partially conserved amino acid sequences of rat, porcine and Drosophila ChAT [44].
• Two of the exons were used to identify polyadenylated human ChAT gene transcripts on Northern blots [45].

References