CTSL1 Antibody
Description
CTSL1 Antibody: Definition and Overview
CTSL1 (Cathepsin L1) antibody is a specialized immunoglobulin designed to target the lysosomal cysteine protease Cathepsin L1 (CTSL1), a key enzyme involved in protein degradation, autophagy, and cellular homeostasis. These antibodies are widely used in research to study CTSL1’s role in pathologies such as cancer, cardiovascular diseases, and viral infections (e.g., SARS-CoV-2). They are available in polyclonal or monoclonal forms, with varying specificities and applications.
Applications of CTSL1 Antibody
CTSL1 antibodies are employed in diverse experimental techniques, including:
Key Protocols:
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Antigen Retrieval: For IHC, TE buffer (pH 9.0) or citrate buffer (pH 6.0) is recommended .
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Tissue Validation: Tested in human skin, liver (HepG2), ovarian cancer, and cardiac tissues .
Cancer Progression
CTSL1 antibodies have elucidated CTSL1’s role in tumor invasion and metastasis:
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Ovarian Cancer: CTSL1 promotes autophagy, epithelial-to-mesenchymal transition (EMT), and chemoresistance via interactions with lncRNAs (e.g., lnc-CTSLP8) .
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Pancreatic Cancer: Elevated CTSL1 correlates with invasion and metastasis, serving as a biomarker .
Cardiac Hypertrophy
CTSL1 antibodies demonstrated that lysosomal CTSL1 attenuates cardiac hypertrophy by facilitating autophagy and proteasomal degradation. AAV9-mediated CTSL1 transfer rescued hypertrophic phenotypes in Ctsl−/− mice .
SARS-CoV-2 Infection
CTSL1 antibodies revealed CTSL1’s role in viral entry:
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Mechanism: CTSL1 cleaves the SARS-CoV-2 spike protein, enhancing virus-host cell fusion .
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Therapeutic Target: CTSL1 inhibitors (e.g., E64d, amantadine) reduce pseudovirus infection in vitro and in vivo .
Therapeutic and Diagnostic Implications
Comparative Analysis of CTSL1 Antibodies
Product Specs
Q&A
How do researchers select the most appropriate CTSL1 antibody for Western blotting?
Selection requires evaluation of antibody specificity, reactivity across species, and validation data. For example, Proteintech’s 10938-1-AP antibody detects human and rat CTSL1 at 36–39 kDa and 29 kDa isoforms . Researchers should:
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Verify immunogen alignment: Ensure the antibody’s immunogen (e.g., CTSL fusion protein Ag1373 ) matches the target epitope.
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Assess species compatibility: Antibodies like United States Biological’s Mouse Anti-Cathepsin L (reactivity: Hu, Ms, Rt ) are suitable for cross-species studies.
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Review validation data: Prioritize antibodies with peer-reviewed publications (e.g., 10938-1-AP has 6 WB, 4 IHC, and 2 IF publications ).
Table 1: Example CTSL1 Antibody Performance in Western Blotting
What methodological steps ensure CTSL1 antibody specificity in immunohistochemistry (IHC)?
Specificity validation involves:
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Antigen retrieval optimization: Proteintech recommends TE buffer (pH 9.0) or citrate buffer (pH 6.0) for human skin tissue .
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Negative controls: Include tissues with CTSL1 knockout or siRNA knockdown.
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Cross-validation: Compare IHC results with orthogonal methods (e.g., ELISA or RNA-seq). For instance, the Assay Genie ELISA kit quantifies rat Ctsl1 with 0.156 ng/mL sensitivity , providing quantitative cross-correlation.
How should researchers resolve discrepancies in CTSL1 expression data across experiments?
Discrepancies often arise from isoform detection variability or post-translational modifications. For example:
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Proteolytic processing: CTSL1 exists as pro-enzyme (38 kDa) and active forms (25–29 kDa) . Antibodies targeting different epitopes may detect distinct isoforms.
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Glycosylation differences: The 36–39 kDa bands in rat muscle suggest glycosylation variants. Use deglycosylation assays (e.g., PNGase F treatment) to confirm.
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Species-specific cross-reactivity: Mouse-specific antibodies (e.g., Sino Biological’s PAb ) may fail in human samples without validation.
Table 2: Common CTSL1 Antibody Cross-Reactivity Issues
What advanced strategies improve CTSL1 detection in multiplex assays?
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Antibody conjugation validation: Ensure fluorophore- or enzyme-conjugated antibodies (e.g., Bioss Inc.’s HRC-conjugated options ) do not alter epitope binding.
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Signal amplification: Pair with tyramide-based systems for low-abundance targets.
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Multiplex ELISA: Use the Assay Genie kit’s protocol with adaptations for simultaneous detection of CTSL1 and related proteases (e.g., Cathepsin B).
How can epitope mapping guide CTSL1 functional studies?
Epitope mapping clarifies whether antibodies target catalytic domains or regulatory regions. For instance:
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Antibodies against the propeptide (e.g., residues 1–96) may block CTSL1 activation .
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Proteintech’s antibody targets an undisclosed epitope; researchers should perform competitive assays with known ligands (e.g., CA-074 for Cathepsin B ) to infer binding regions.
What genetic engineering approaches enhance CTSL1 antibody utility?
Recent work fused propeptides to antibody CDR3 regions to create inhibitors . For CTSL1:
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Design propeptide-antibody fusions: Link CTSL1 propeptide (residues 1–114) to heavy chains of clinical antibodies (e.g., trastuzumab).
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Test inhibitory potency: Measure IC50 values using fluorogenic substrates (e.g., Z-FR-AMC for CTSL1 activity).
How to validate CTSL1 knockout models using antibodies?
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Step 1: Use antibodies with well-characterized epitopes (e.g., 10938-1-AP ) in WB and IHC.
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Step 2: Quantify residual CTSL1 via ELISA (detection limit: 0.156 ng/mL ).
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Step 3: Confirm with activity assays (e.g., fluorogenic substrate cleavage in KO vs. WT lysates).
What computational tools assist in CTSL1 antibody experimental design?
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BLAST alignment: Verify immunogen sequence homology (e.g., human vs. rodent CTSL1).
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Structural modeling: Predict antibody-epitope interactions using SWISS-MODEL and PyMOL.
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Dose-response analysis: Fit ELISA data to four-parameter logistic curves for precise quantification.
Data Contradiction Analysis Framework
| Scenario | Root Cause | Resolution Strategy |
|---|---|---|
| Inconsistent WB bands | Isoform-specific detection | Deglycosylation + knockout validation |
| Low IHC signal | Suboptimal antigen retrieval | Test multiple buffers (pH 6.0–9.0) |
| ELISA vs. WB discrepancy | Post-translational modifications | Combine with activity assays |
Product Science Overview
Cathepsin L is a member of the papain superfamily of cysteine proteases, which are enzymes that break down proteins by cleaving peptide bonds. It is synthesized as an inactive proenzyme and becomes active upon cleavage of its propeptide. Cathepsin L is found in lysosomes, where it plays a crucial role in the degradation of intracellular and extracellular proteins .
Cathepsin L is involved in various physiological processes, including:
- Protein Degradation: It hydrolyzes a number of proteins, including the proform of urokinase-type plasminogen activator, which is activated by Cathepsin L cleavage .
- Immune Response: It proteolytically inactivates alpha 1-antitrypsin and secretory leucoprotease inhibitor, two major protease inhibitors of the respiratory tract .
- Disease Mechanisms: Cathepsin L has been implicated in the pathology of several diseases, including cancer, osteoporosis, and viral infections such as SARS-CoV-2 .
The Mouse Anti-Human Cathepsin L antibody is a monoclonal antibody that specifically detects human Cathepsin L. It is produced by immunizing mice with human Cathepsin L and then harvesting the antibody-producing cells from the mice. These cells are fused with myeloma cells to create hybridomas, which can be cultured to produce large quantities of the antibody .
The Mouse Anti-Human Cathepsin L antibody is used in various research applications, including:
- Western Blotting: It detects both the pro and active forms of recombinant human and mouse Cathepsin L in Western blots .
- Immunohistochemistry: It is used to detect Cathepsin L in tissue sections, such as human kidney tissue .
- Immunoprecipitation: It is used to isolate Cathepsin L from cell lysates or conditioned media .
The Mouse Anti-Human Cathepsin L antibody is highly specific for human Cathepsin L and does not cross-react with other related lysosomal cysteine proteases, such as Cathepsin B, C, L2, O, S, or X/Z/P . This specificity makes it a valuable tool for studying Cathepsin L in various biological contexts.
