Applications : WB
Sample type: cells
Review: To validate the proteomics results, western blot was performed to evaluate the expression levels of CKM, MME, MPO, and GAPDH was selected as the internal reference protein.
CKM (creatine kinase muscle-type) catalyzes the reversible transfer of phosphate between ATP and creatine, a critical energy buffer in muscle tissues. Antibodies against CKM enable researchers to detect its expression patterns, subcellular localization, and dynamic changes under physiological or pathological conditions (e.g., myocardial injury or muscular dystrophy) . Methodologically, CKM antibodies are validated for applications such as:
Western blotting to quantify CKM protein levels in tissue lysates.
Immunohistochemistry (IHC) to map CKM distribution in muscle biopsies.
Immunofluorescence (IF) for co-localization studies with mitochondrial markers .
Experimental variability arises from improper antibody handling, insufficient validation, or inadequate controls. Key design considerations:
Sample Preparation: Use fresh-frozen muscle tissues to prevent epitope degradation. Avoid repeated freeze-thaw cycles of lysates .
Antibody Dilution: Perform checkerboard titrations (e.g., 1:100 to 1:2000) to identify optimal signal-to-noise ratios .
Controls: Include:
Three-tier validation is recommended:
Genetic Knockout Validation: Compare staining or blot signals in wild-type vs. CKM-deficient tissues .
Peptide Blocking: Pre-incubate antibodies with excess CKM peptide; >90% signal reduction confirms specificity .
Orthogonal Assays: Correlate antibody-based results with mRNA quantification (qPCR) or enzymatic activity assays .
Discrepancies often stem from antibody cross-reactivity or post-translational modifications (PTMs). Follow this workflow:
Re-validate Antibodies: Confirm lot-to-lot consistency using recombinant CKM protein.
PTM Analysis: Use phospho-specific antibodies or protease digestion to rule out epitope masking.
Cross-Reactivity Screening: Test antibodies against recombinant CK-BB and CK-MB isoforms .
| Issue | Diagnostic Test | Solution |
|---|---|---|
| False-positive IHC | Staining in CKM-knockout tissues | Switch to monoclonal antibodies |
| Multiple WB bands | siRNA knockdown of off-target proteins | Optimize blocking buffer (5% BSA) |
Multiplexing CKM with markers like troponin or myosin requires:
Spectral Compatibility: Use conjugates with minimal overlap (e.g., AF488 for CKM, AF647 for troponin).
Sequential Staining: Apply CKM antibodies first to avoid epitope competition.
Signal Normalization: Include reference standards (e.g., recombinant CKM spiked into samples) .
Formalin fixation induces protein crosslinking, often masking linear epitopes. Solutions:
Antigen Retrieval: Use high-pH Tris-EDTA buffer (pH 9.0) for 20 min at 95°C.
Antibody Selection: Prioritize antibodies validated for paraffin-embedded tissues (e.g., clones MAK33 or Y14) .
Epitope Mapping: Choose antibodies targeting unstructured regions (e.g., amino acids 10–59) .
Use platforms like:
IEDB Analysis Resource (iedb.org) to predict linear epitopes from CKM’s amino acid sequence.
AlphaFold2 to model conformational epitopes in the 3D structure of CKM.
BLAST to check for homology with unrelated proteins (e.g., CK-BB shares 75% sequence identity) .
Longitudinal rigor requires:
Batch Consistency: Use antibodies from the same lot for all timepoints.
Stability Testing: Store aliquots at -80°C with 0.02% sodium azide to prevent aggregation.
Quantitative Normalization: Express CKM levels relative to housekeeping proteins (e.g., GAPDH) and tissue weight .
Parallel Detection: Compare results from two independent antibody clones (e.g., polyclonal vs. monoclonal).
Functional Assays: Couple antibody-based detection with creatine kinase activity measurements.
Meta-Analysis: Cross-reference findings with public datasets (e.g., Human Protein Atlas) .
Design a panel targeting: