QPCT Gene
Introduction
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">QPCT Gene</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td>QPCT</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Glutaminyl Cyclase</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>QC, GCPII, GCPIII</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>2p22.2</td>
</tr>
<tr>
<td class="label">Gene ID (NCBI)</td>
<td>25788</td>
</tr>
<tr>
<td class="label">HGNC ID</td>
<td>18329</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000125827</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q96KH6</td>
</tr>
<tr>
<td class="label">Category</td>
<td>Enzyme</td>
</tr>
<tr>
<td class="label">Compound</td>
<td>Development Status</td>
</tr>
<tr>
<td class="label">PQ912</td>
<td>Phase 2a clinical trial</td>
</tr>
<tr>
<td class="label">PBD150</td>
<td>Preclinical</td>
</tr>
<tr>
<td class="label">compound 5</td>
<td>Preclinical</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
Qpct Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
...QPCT Gene
Introduction
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">QPCT Gene</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td>QPCT</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Glutaminyl Cyclase</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>QC, GCPII, GCPIII</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>2p22.2</td>
</tr>
<tr>
<td class="label">Gene ID (NCBI)</td>
<td>25788</td>
</tr>
<tr>
<td class="label">HGNC ID</td>
<td>18329</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000125827</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q96KH6</td>
</tr>
<tr>
<td class="label">Category</td>
<td>Enzyme</td>
</tr>
<tr>
<td class="label">Compound</td>
<td>Development Status</td>
</tr>
<tr>
<td class="label">PQ912</td>
<td>Phase 2a clinical trial</td>
</tr>
<tr>
<td class="label">PBD150</td>
<td>Preclinical</td>
</tr>
<tr>
<td class="label">compound 5</td>
<td>Preclinical</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
Qpct Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
Glutaminyl Cyclase (QPCT) is a gene encoding a crucial enzyme involved in the post-translational modification of proteins. The enzyme catalyzes the conversion of N-terminal glutamine residues to pyroglutamate (pGlu), a modification that significantly alters protein properties and is highly relevant to neurodegenerative disease research. [@qsox2006]
Protein Overview
The QPCT-encoded protein, also known as glutaminyl cyclase (QC), is a 360-amino acid enzyme that belongs to the family of metal-dependent hydrolases. QPCT is localized primarily in the Golgi apparatus and extracellular space, where it performs its enzymatic function of converting N-terminal glutamine to pyroglutamate [1]. This modification, known as pyroglutamylation, protects proteins from degradation by aminopeptidases and can dramatically increase the aggregation propensity of certain proteins.
Molecular Function
Enzymatic Activity
Glutaminyl cyclase catalyzes the intramolecular cyclization of N-terminal glutamine residues to form pyroglutamate (pGlu) residues. This reaction occurs spontaneously under physiological conditions but is dramatically accelerated by QPCT [1]. The enzyme shows specificity for glutamine at the N-terminus, with much slower activity toward glutamate, which forms pyroglutamate through a different mechanism.
Biological Significance
The pyroglutamate modification has several important biological consequences:
Stability Enhancement: pGlu-modified proteins exhibit increased resistance to aminopeptidase degradation, extending their half-life in vivo [2].
Aggregation Propensity: The modification creates highly hydrophobic N-termini that promote protein aggregation and fibril formation [3].
Cellular Localization: QPCT is expressed in various tissues, with high expression in the brain, particularly in regions vulnerable to neurodegeneration [4].Disease Associations
Alzheimer's Disease
QPCT has emerged as a significant therapeutic target in Alzheimer's disease (AD). The pyroglutamate-modified [amyloid-beta](/proteins/amyloid-beta) (pE3-Aβ) species is one of the most aggregation-prone and toxic forms of Aβ found in amyloid plaques [3][5]. Key points include:
- pE3-Aβ Formation: QPCT catalyzes the formation of pE3-Aβ from Aβ1-40 and Aβ1-42, generating highly neurotoxic oligomers and fibrils [5].
- Seeding Activity: pE3-Aβ acts as a "seed" that accelerates the aggregation of wild-type Aβ, promoting plaque formation [6].
- Therapeutic Targeting: Several QPCT inhibitors have been developed as potential AD therapeutics, including PQ912, which has undergone clinical trials [7].
Amyotrophic Lateral Sclerosis (ALS)
While less characterized than in AD, QPCT may play a role in ALS through its involvement in protein quality control mechanisms. The enzyme's activity may contribute to the aggregation of [TDP-43](/proteins/tdp-43) and other ALS-associated proteins [8].
Other Neurodegenerative Conditions
- Parkinson's Disease: Potential involvement in [alpha-synuclein](/mechanisms/alpha-synuclein) modification
- Huntington's Disease: Possible role in mutant [huntingtin](/proteins/huntingtin-protein) aggregation
Expression Patterns
QPCT shows widespread expression in the human body, with notable levels in:
- Brain: Cerebral [cortex](/brain-regions/cortex), [hippocampus](/brain-regions/hippocampus), basal ganglia, and cerebellum
- Peripheral Tissues: Liver, kidney, and endocrine glands
- Cell Types: [Neurons](/entities/neurons), [astrocytes](/entities/astrocytes), and [microglia](/entities/microglia)
Expression is particularly elevated in regions associated with amyloid pathology in AD brains [4].
Therapeutic Implications
QPCT Inhibitors
The development of QPCT inhibitors represents an active area of AD drug discovery:
Mechanism of Action
QPCT inhibitors work by:
Reducing pE3-Aβ formation
Decreasing amyloid plaque burden
Improving synaptic function
Reducing neuroinflammationResearch Highlights
- Genetic Studies: QPCT polymorphisms have been associated with age of onset in AD [9].
- Animal Models: QPCT knockout mice show reduced pE3-Aβ formation and improved cognitive function [10].
- Biomarker Potential: pE3-Aβ in cerebrospinal fluid may serve as a biomarker for QPCT activity [11].
Summary
The QPCT gene encodes glutaminyl cyclase, an enzyme critical for the formation of pyroglutamate-modified proteins. Its role in generating toxic pE3-Aβ species makes it a compelling therapeutic target in Alzheimer's disease. QPCT inhibitors represent a promising approach to modifying disease progression in AD and potentially other neurodegenerative conditions characterized by protein aggregation.
Background
The study of Qpct Gene has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
External Links
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
- [Alzheimer's Disease Neuroimaging Initiative](https://adni.loni.usc.edu/) - Research data
- [Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data
See Also
- [QPCT Protein](/proteins/qpct-protein)
- [Protein Quality Control](/mechanisms/protein-quality-control-network)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Amyloid Cascade Hypothesis](/mechanisms/amyloid-cascade)
- [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
- [Pyroglutamate-Modified Proteins](/content/proteins)
- Glutaminyl Cyclase Inhibitors
- [Protein Aggregation Mechanisms](/content/mechanisms)
- [QPCT Gene - NCBI](https://www.ncbi.nlm.nih.gov/gene/25788)
- [HGNC QPCT](https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:18329)
- [UniProt Q96KH6](https://www.uniprot.org/uniprotkb/Q96KH6/entry)