CPE Antibody
Description
What is CPE Antibody?
CPE antibodies are immunoreagents targeting carboxypeptidase E, a metalloprotease that cleaves C-terminal arginine/lysine residues from peptide precursors. This enzyme is essential for processing neuroendocrine peptides like insulin, enkephalins, and neurotransmitters . Antibodies against CPE enable researchers to:
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Localize CPE in tissues (e.g., brain, pancreas)
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Quantify protein expression levels
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Study its role in neurological disorders, cancer, and metabolic diseases .
Key Applications of CPE Antibodies
CPE antibodies are validated for multiple experimental workflows:
Neurological Dysfunction
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CPE Knockout Mice:
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Hippocampal neurons in CPE flox/flox mice showed reduced MAP2 (microtubule-associated protein 2) and GFAP (glial fibrillary acidic protein) intensity, indicating impaired neuronal and glial function .
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Deficits in BDNF/TrkB signaling and neurogenesis were observed, linking CPE to learning/memory disorders .
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Cancer Research
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Pro-Survival Role:
Diagnostic Utility
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CPE antibodies detected reduced enzyme levels in Alzheimer’s disease models, correlating with amyloid-beta pathology .
Validation and Quality Control
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Specificity: Anti-CPE antibodies show <5% cross-reactivity with related enzymes like CPM .
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Reproducibility: Rigorous lot-to-lot testing ensures consistent performance in detecting CPE across species .
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Functional Assays: Neutralizing antibodies (e.g., 6E10C12, 2G11G7) inhibit CPE-mediated peptide processing in in vitro models .
Challenges and Considerations
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Isoform Detection: Some antibodies may not distinguish between membrane-bound and soluble CPE isoforms .
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Species Cross-Reactivity: Verify antibody compatibility (e.g., mouse vs. human CPE) before experimental design .
Future Directions
Emerging studies explore CPE antibodies for:
Product Specs
Target Background
- Our findings suggest a novel role for Carboxypeptidase E that primarily influences the expression of motility-associated genes through multiple signaling pathways. PMID: 28656234
- This study has identified a human CPE/NF-alpha1 gene mutation that could lead to the co-occurrence of dementia and depression, highlighting the importance of this gene in cognitive function. PMID: 27922637
- CPE, through its N'-terminal sequence, forms aggregates with Wnt3a, potentially leading to endoplasmic reticulum (ER) stress and subsequent loss of function. PMID: 27375026
- We have identified a novel single nucleotide polymorphism (SNP) in the CPE gene that results in the loss of its neuroprotective function in cells and may contribute to neurological disorders in humans. PMID: 28114332
- High levels of CPE expression were associated with a poor prognosis in early-stage cervical cancer. CPE may serve as a biomarker for predicting pelvic lymph node metastasis (PLNM) and overall survival in these patients. PMID: 26695643
- Low carboxypeptidase E expression is linked to recurrence in early-stage hepatocellular carcinoma. PMID: 26803519
- Downregulation of liver carboxypeptidase E may reduce the secretion of serum cholecystokinin and contribute to the formation of cholesterol gallstones. PMID: 26228366
- Downregulation of CPE regulates cell proliferation and chemosensitivity in pancreatic cancer. PMID: 25374060
- Disruption of insulin receptor (IR) expression in beta cells has a direct impact on the expression of the convertase enzyme carboxypeptidase E (CPE) by inhibiting the eukaryotic translation initiation factor Eif4g1. PMID: 24843127
- Upregulation of CPE promotes cell proliferation and tumorigenicity in colorectal cancer. PMID: 24006921
- Data suggest that a splice variant of carboxypeptidase E (CPE-DeltaN) may be a potential prognostic marker for colorectal cancer patients. PMID: 23852859
- CPE is essential in the processing and targeting of neuropeptides and neurotrophins, suggesting its potential involvement in the pathological progression of Alzheimer's disease. PMID: 22998035
- CPE forms a complex, likely through sequences located at its N-terminal domain, with Wnt3a and the extracellular cysteine-rich domain of Fz1. PMID: 22824791
- Neither high glucose nor insulin (with low glucose) regulates beta-cell CPE (but either upregulates CPD). PMID: 21628999
- An N-terminal truncated carboxypeptidase E splice isoform induces tumor growth and serves as a biomarker for predicting future metastasis in human cancers. PMID: 21285511
- CPE may play a role in promoting tumor growth and invasion. PMID: 21061162
- Carboxypeptidase E is differentially expressed in subcutaneous and visceral fat of obese subjects. PMID: 12530526
- Protein binding with Con A in seminal plasma. PMID: 14690244
- cDNA microarray analysis led to the identification of 2 novel biomarkers that should facilitate molecular diagnosis and further research on pulmonary neuroendocrine tumors. PMID: 15492986
- A possible role for mutations in CPE in the development of coronary heart disease. PMID: 17957445
- The severity of coronary atherosclerosis, as estimated by Gensini score, was significantly influenced by the presence of the A2925G mutant and G2855A mutant of the CPE gene. PMID: 18080843
- Polymorphism in the CPE exon5 gene may contribute to the angiographical characteristics of coronary atherosclerosis in the Chinese population. PMID: 18501121
- Carboxypeptidase E degradation contributes to palmitate-induced beta-cell ER stress and apoptosis; CPE is a major link between hyperlipidemia and beta-cell death pathways in diabetes. PMID: 18550819
- CPH-Abs may allow discrimination of a more latent subset of adult-onset autoimmune diabetes (LADA). PMID: 19120309
- Carboxypeptidase E may be a key molecule in regulating Caspr2 (carboxypeptidase E) trafficking to the cell membrane. PMID: 19166515
- Missense polymorphism encoding altered activity. PMID: 11462236
Q&A
What validation steps are essential when using CPE antibodies in immunohistochemistry?
Validation requires three parallel approaches:
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Positive/Negative Controls: Compare staining in tissues or cell lines with known CPE expression (e.g., HepG2 hepatocellular carcinoma cells ) versus CPE-knockout models .
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Cross-Reactivity Testing: Verify antibody specificity using peptide blocking assays. For example, R&D Systems’ MAB3587 binds human CPE residues 42–453 but may cross-react with rodent isoforms .
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Dilution Optimization: Titrate antibody concentrations (e.g., 0.1–10 µg/mL) to balance signal-to-noise ratios. The AF3587 antibody achieved optimal staining at 10 µg/mL in mouse embryo sections .
Table 1: CPE Antibody Performance in Key Applications
How can researchers optimize CPE antibody concentrations for Western Blot?
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Step 1: Perform a dilution series (e.g., 1:500–1:5,000) using lysates from CPE-overexpressing cell lines (e.g., HEK293T transfected with human CPE).
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Step 2: Normalize signals against loading controls (e.g., β-actin). For MAB3587, 1 µg/mL detected CPE in human glioblastoma lysates without nonspecific bands .
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Step 3: Pre-absorb antibodies with recombinant CPE protein to confirm band specificity .
How should discrepancies in CPE localization between IHC and Western Blot be resolved?
Conflicting data often arise from isoform-specific detection or post-translational modifications:
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Case Study: AF3587 localized CPE to HepG2 cell membranes via IHC , while WB detected a 50 kDa cytoplasmic isoform . This suggests alternative splicing or cleavage events.
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Methodological Fix: Combine RNAi knockdown (to silence specific isoforms) with mass spectrometry to identify detected variants .
What strategies enhance CPE antibody specificity in flow cytometry?
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Fixation/Permeabilization: Methanol fixation improved AF3587’s intracellular staining in A172 glioblastoma cells .
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Multicolor Panels: Pair CPE antibodies with lineage markers (e.g., CD133 for stem cells) to exclude false positives.
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Competition Assays: Pre-incubate antibodies with recombinant CPE to quantify nonspecific binding .
How do genetic variants impact CPE antibody performance?
The T980C polymorphism (linked to Alzheimer’s risk) truncates CPE, altering antibody binding:
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Experimental Design:
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Result: T980C mutants show reduced detection by antibodies targeting the C-terminus .
Can CPE antibodies be integrated into neutralization assays for viral studies?
Yes, with modifications:
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Case Study: A CPE-based micro-neutralization assay evaluated SARS-CoV-2 antibodies. Viral cytopathic effect (CPE) was monitored in Vero E6 cells, with antibody efficacy quantified via TCID50 .
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Critical Step: Include a CPE-negative control (e.g., untreated cells) to normalize results .
