MYL2 Antibody

What is MYL2 and why is it a significant target for antibody-based detection in cardiovascular research?

MYL2 (Myosin Light Chain 2) is a regulatory protein essential for cardiac and skeletal muscle contraction. It functions as the regulatory light chain component of myosin, playing crucial roles in muscle contraction mechanisms and calcium sensitivity regulation. MYL2 has significant research importance because:

• It serves as a cardiac-specific marker with a molecular weight of approximately 19 kDa (calculated), though typically observed at 18-20 kDa in SDS-PAGE analysis

• Mutations in MYL2 are associated with hypertrophic cardiomyopathy (HCM), making it valuable for studying cardiac pathologies

• It exists in phosphorylated states (particularly at Serine 18) that regulate its function and can be specifically detected

• It's involved in multiple cellular pathways including cardiac muscle contraction, focal adhesion, and regulation of actin cytoskeleton

The protein contains three EF-hand domains that are critical for its function, with the C-terminal domain playing a particularly important role in protein localization and stability .

What are the primary considerations when selecting an MYL2 antibody for a specific research application?

When selecting an MYL2 antibody, researchers should consider:

Additionally, consider storage requirements (most require -20°C storage in glycerol-containing buffers) and stability information (typically 12 months from receipt) .

What are typical MYL2 expression patterns that should be expected in positive control tissues?

When validating MYL2 antibodies, expect these characteristic expression patterns:

Proper controls should include: (1) Known positive samples as listed above, (2) Negative control tissues, (3) Primary antibody omission controls, and (4) Blocking peptide controls where available .

How should immunohistochemical protocols be optimized specifically for MYL2 detection in cardiac tissues?

For optimal MYL2 immunohistochemistry in cardiac tissues:

• Tissue preparation:

  • Fixation: Use appropriate fixatives that preserve MYL2 epitopes

  • Sectioning: 4-6 μm sections are typically suitable

• Antigen retrieval optimization:

  • Primary recommendation: TE buffer pH 9.0

  • Alternative method: Citrate buffer pH 6.0

  • Temperature and time: 95-100°C for 15-20 minutes

• Blocking optimization:

  • Block endogenous peroxidases: 3% H₂O₂ at 37°C for 15 minutes

  • Protein blocking: 3% bovine serum albumin in PBS at 37°C for 20 minutes

• Antibody incubation:

  • Primary antibody dilution range: 1:20-1:200 for IHC applications

  • Incubation conditions: 4°C overnight for optimal results

  • Secondary antibody: Match to host species, typically incubate at 37°C for 20 minutes

• Detection system:

  • DAB method yields brown staining suitable for counterstaining with hematoxylin

  • Fluorescent detection provides opportunities for co-localization studies

• Quantification approach:

  • Measure positive-stained integrated optical density (IOD) using image analysis software

  • Normalize expression between samples using appropriate controls

Researchers should perform antibody titration experiments and include both positive (heart tissue) and negative controls in each experiment to validate specificity .

What are the critical variables in Western blot protocols that affect MYL2 detection sensitivity and specificity?

For optimal Western blot detection of MYL2:

• Sample preparation considerations:

  • Extraction buffer composition: Use buffers that efficiently extract myofibrillar proteins

  • Protease inhibitors: Critical to prevent degradation

  • Phosphatase inhibitors: Essential when studying phosphorylated forms of MYL2

• Gel electrophoresis parameters:

  • Gel percentage: 12-15% gels provide optimal resolution for the 18-20 kDa MYL2 protein

  • Loading amount: 10-30 μg total protein from heart tissue typically provides detectable signals

  • Running conditions: Lower voltage for better resolution of this small protein

• Antibody optimization:

  • Primary antibody dilution range: 1:2000-1:20,000 (highly variable between antibodies)

  • Primary antibody incubation: Overnight at 4°C often yields best results

  • Secondary antibody selection: HRP-conjugated or fluorescently-labeled antibody matching host species

• Detection system selection:

  • Enhanced chemiluminescence: Provides good sensitivity for most applications

  • Fluorescent detection: Offers better quantitative linearity and multiplexing capability

• Quantification methodology:

  • Normalization: Beta-actin (42 kDa) is commonly used as loading control

  • Quantification: Calculate MYL2/beta-actin ratios for relative expression analysis

• Validation approaches:

  • Positive control: Heart tissue from the appropriate species

  • Negative control: Tissues not expressing MYL2

  • Blocking peptide: To confirm antibody specificity

For phospho-specific detection, include appropriate controls such as lambda phosphatase-treated samples and kinase activation/inhibition experiments .

How can I optimize Flow Cytometry protocols for detecting MYL2 in cardiomyocytes and muscle cell lines?

For optimal flow cytometry detection of MYL2:

• Cell preparation considerations:

  • Cell types: C2C12 cells have been validated for FC analysis

  • Fixation: 4% paraformaldehyde for 15 minutes at room temperature

  • Permeabilization: Critical for intracellular MYL2 detection; use 0.1-0.5% Triton X-100 or saponin-based buffers

• Antibody parameters:

  • Recommended concentration: 0.40 μg per 10^6 cells in 100 μl suspension

  • Incubation conditions: 30-60 minutes at room temperature or 4°C overnight

  • Secondary antibody: Fluorophore-conjugated antibody matching the host species

• Controls required:

  • Unstained cells: For autofluorescence assessment

  • Isotype control: Matching the primary antibody's host and isotype

  • Secondary-only control: To assess non-specific binding

  • Positive control: Cell types known to express MYL2

• Gating strategy:

  • Forward/side scatter: To identify intact single cells

  • Viability marker: To exclude dead cells

  • Expression analysis: Compare signal intensity to controls

• Optimization considerations:

  • Titrate antibody to determine optimal concentration

  • Compare different permeabilization methods

  • Assess surface vs. intracellular staining protocols

• Multiparameter considerations:

  • Co-staining with cardiac markers (e.g., cardiac troponin)

  • Cell cycle analysis in combination with MYL2 expression

  • Phospho-specific detection in combination with total protein

For phosphorylated MYL2 detection, use phospho-specific antibodies and include appropriate controls such as phosphatase-treated samples .

How can MYL2 antibodies be used to study the molecular mechanisms of hypertrophic cardiomyopathy?

MYL2 antibodies serve as powerful tools for investigating hypertrophic cardiomyopathy (HCM) mechanisms:

• Expression level analysis:

  • Western blot quantification: MYL2 levels are often altered in HCM patients (down-regulated in heart failure patients to approximately 69% of control levels)

  • Immunohistochemistry: Can reveal spatial distribution changes in affected tissue

• Mutation-specific investigations:

  • Frameshift variant effects: The p.Pro144Argfs*57 variant shows marked reduction in protein expression levels compared to controls, indicating protein degradation

  • Missense variant effects: Variants like p.Gly162Arg affect localization rather than stability

  • Stop-gain variants: p.E22*, p.K62*, p.E97* variants show impaired localization despite stable expression

• Phosphorylation status assessment:

  • Phospho-specific antibodies: Enable detection of regulatory phosphorylation at Serine 18, which may be altered in disease states

  • Phosphorylation changes: Alterations can be quantified relative to total MYL2

• Domain-function relationship studies:

  • C-terminal EF-hand domain: Critical for protein localization and stability as revealed by variant studies

  • Recessive vs. dominant variants: Different molecular mechanisms (loss-of-function vs. dominant-negative)

• Protein degradation mechanisms:

  • Proteasome inhibition: Rescues degradation of frameshift variants, indicating post-translational effects

  • Stability assessment: Frameshift variants show accelerated degradation compared to missense variants

These approaches have revealed that recessive MYL2 variants typically result in protein degradation, while dominant variants more commonly affect protein function while maintaining stability - critical distinctions for understanding disease mechanisms .

What experimental approaches can resolve contradictory findings regarding MYL2 expression levels in different cardiac disease models?

To resolve contradictory findings regarding MYL2 expression in cardiac disease models:

• Standardize quantification methodologies:

  • Normalization approach: Consistently use beta-actin (42 kDa) or other stable reference proteins

  • Quantification method: Calculate MYL2/reference protein ratios using standardized image analysis software

  • Expression reporting: Report relative values with clearly defined controls (e.g., normalize control group as 100% ± standard deviation)

• Implement multiple detection methods:

  • Complementary techniques: Combine Western blot, IHC, and qPCR data

  • Protein vs. mRNA: Compare protein expression with transcript levels to identify post-transcriptional regulation

  • Phosphorylated vs. total protein: Assess both forms to distinguish between expression and activation changes

• Control for confounding variables:

  • Disease stage stratification: Separate early vs. late disease stages

  • Anatomical specificity: Precisely define and consistently sample specific cardiac regions

  • Patient/animal characteristics: Control for age, sex, comorbidities, and medications

  • Technical variables: Standardize sample collection, processing time, and storage conditions

• Implement rigorous statistical analysis:

  • Appropriate statistical tests: Use Student's t-test for two-group comparisons

  • Power analysis: Ensure adequate sample sizes

  • Multiple testing correction: Apply when examining multiple parameters

• Advanced molecular analyses:

  • Protein stability studies: Use cycloheximide chase assays to determine protein half-life

  • Proteasome inhibition experiments: Determine if protein degradation is proteasome-dependent

  • Subcellular fractionation: Distinguish between cytosolic and myofibrillar fractions

These approaches can help determine whether contradictory findings reflect biological differences between models or technical variables in experimental design .

How can phospho-specific MYL2 antibodies be utilized to understand the regulatory role of phosphorylation in cardiac function?

Phospho-specific MYL2 antibodies enable sophisticated studies of phosphoregulation in cardiac function:

• Phosphorylation site-specific detection:

  • Target specificity: Antibodies recognizing phosphorylated Serine 18 within the A-T-SP-N-V motif are particularly valuable

  • Validation approach: Confirm specificity using dephosphorylated controls (lambda phosphatase treatment)

  • Recommended dilutions: 1:500-1:1000 for Western blot, 1:50-1:100 for IHC applications

• Physiological regulation studies:

  • Calcium dependence: Correlate phosphorylation status with calcium levels

  • β-adrenergic signaling: Examine phosphorylation changes following adrenergic stimulation

  • Force-frequency relationship: Study how mechanical loading affects phosphorylation status

• Pathological alterations assessment:

  • Disease model comparison: Analyze phosphorylation changes in hypertrophy, heart failure, and ischemia

  • Mutation influence: Determine how MYL2 mutations affect phosphorylation patterns

  • Post-translational modification interplay: Examine relationship between phosphorylation and other modifications

• Structural biology applications:

  • Conformational changes: Use phospho-specific antibodies to probe structural alterations

  • Domain interactions: Investigate how phosphorylation affects protein-protein interactions

  • Distance measurements: Study how phosphorylation alters distances between functional residues (e.g., the p.Ile158Thr variant increases the distance between the 158th residue and Ser15 from 27.5Å to 30.0Å)

• Therapeutic target validation:

  • Kinase inhibitor effects: Measure phosphorylation changes following treatment

  • Phosphatase modulation: Examine consequences of enhanced or reduced dephosphorylation

  • Correlation with functional outcomes: Link phosphorylation status to contractile parameters

• Multiplexed analysis approaches:

  • Dual staining: Combine phospho-specific with total MYL2 antibodies

  • Co-localization studies: Examine spatial relationship with sarcomeric structures

  • Multi-site phosphorylation: Investigate coordination between different phosphorylation sites

These approaches reveal how phosphorylation at Ser18 regulates MYL2 function and how alterations in this regulatory mechanism contribute to cardiac pathophysiology .

What are the most common technical challenges in Western blot detection of MYL2 and their methodological solutions?

For MYL2 specifically, ensure optimal sensitivity by following recommended dilutions, which can vary widely between antibodies (1:2000-1:20,000). Include appropriate positive controls (rat heart tissue) and verify the molecular weight (18-20 kDa) .

How can researchers validate antibody specificity for MYL2 and distinguish between MYL2 and other myosin light chain family members?

Comprehensive validation strategies for MYL2 antibody specificity:

• Genetic validation approaches:

  • Knockout/knockdown controls: Compare staining in MYL2-deficient vs. wild-type samples

  • Overexpression systems: Test antibody reactivity against tagged MYL2 vs. empty vector controls

  • Mutation models: Examine antibody recognition of variant forms (frameshift variants might show reduced recognition)

• Biochemical validation methods:

  • Peptide competition: Pre-incubate antibody with immunizing peptide to block specific binding

  • Immunoprecipitation-mass spectrometry: Confirm antibody pulls down MYL2 protein

  • Western blot: Verify single band at expected molecular weight (18-20 kDa)

• Cross-reactivity assessment:

  • Multi-tissue expression analysis: Compare staining patterns with known MYL2 distribution

  • Recombinant protein panel: Test against related myosin light chain family members

  • Species cross-reactivity: Validate across species when using in different models

• Family member distinction strategies:

  • Isoform-specific epitopes: Use antibodies targeting unique regions

  • Molecular weight differentiation: MYL2 appears at 18-20 kDa, which may differ from other family members

  • Expression pattern comparison: MYL2 is predominantly expressed in cardiac/slow skeletal muscle

  • Phosphorylation sites: Target phospho-Ser18 which may be unique to MYL2

• Application-specific validation:

  • Multi-application confirmation: Validate findings across WB, IHC, and IF applications

  • Multiple antibody concordance: Compare results using different antibodies targeting different epitopes

  • Positive control tissues: Use rat heart for WB, human heart for IHC, and C2C12 cells for FC

These approaches are essential when studying MYL2 in experimental contexts where multiple myosin light chain family members may be present, ensuring that experimental findings are truly specific to MYL2 .

What are the key considerations for long-term storage and handling of MYL2 antibodies to maintain optimal performance across experimental replicates?

To maintain optimal MYL2 antibody performance over time:

• Storage temperature requirements:

  • Long-term storage: Maintain at -20°C as specified by manufacturers

  • Short-term storage: Working dilutions can be kept at 4°C for limited periods

  • Stability duration: Most formulations remain stable for 12 months from receipt when stored properly

• Buffer composition considerations:

  • Glycerol content: Many MYL2 antibodies are supplied in 50% glycerol to prevent freezing at -20°C

  • Preservatives: Typically contain 0.02% sodium azide to prevent microbial growth

  • pH maintenance: Usually buffered at pH 7.3-7.4 for optimal stability

• Aliquoting strategies:

  • Size considerations: Prepare small aliquots to minimize freeze-thaw cycles

  • Necessity assessment: Some formulations specifically note "Aliquoting is unnecessary for -20°C storage"

  • Container selection: Use sterile, low-protein binding tubes

• Handling practices:

  • Temperature transitions: Allow antibodies to equilibrate to room temperature before opening

  • Centrifugation: Briefly centrifuge vials before opening to collect liquid at the bottom

  • Contamination prevention: Use sterile technique when handling antibody solutions

  • Freeze-thaw minimization: Limit cycles as much as possible

• Working dilution management:

  • Preparation timing: Make fresh working dilutions for each experiment when possible

  • Diluent selection: Use high-quality blocking buffer compatible with your application

  • Storage duration: Use working dilutions within recommended timeframes

  • Documentation: Record lot numbers and preparation dates for all working solutions

• Quality control procedures:

  • Performance monitoring: Regularly test antibody activity using standard samples

  • Positive control inclusion: Include consistent positive controls in each experiment

  • Standardization: Maintain consistent protocols across experiments

  • Bridging studies: When changing lots, perform side-by-side comparison with previous lot

Following these practices ensures reproducible results when using MYL2 antibodies across multiple experiments and extended research timelines .

How can MYL2 antibodies be utilized in studying cardiac regeneration and cardiomyocyte differentiation from stem cells?

MYL2 antibodies offer powerful approaches for cardiac regeneration and differentiation research:

• Differentiation marker validation:

  • Temporal expression analysis: Track MYL2 expression during progressive differentiation stages

  • Quantitative assessment: Use Western blot to measure increasing MYL2 levels as differentiation proceeds

  • Spatial organization: Use immunofluorescence to monitor sarcomeric incorporation of MYL2

  • Population analysis: Apply flow cytometry to quantify percentage of MYL2-positive cells (0.40 μg per 10^6 cells)

• Cardiac lineage commitment assessment:

  • Co-expression studies: Combine MYL2 staining with other cardiac markers

  • Isoform transitions: Monitor switch from fetal to adult cardiac isoforms

  • Maturation evaluation: Assess phosphorylation status using phospho-specific antibodies

  • Functional correlation: Link MYL2 expression patterns to contractile properties

• Transgenic reporter validation:

  • Reporter fidelity confirmation: Compare endogenous MYL2 protein expression with reporter signals

  • Promoter activity assessment: Correlate MYL2 protein with transcriptional activity

  • Single-cell heterogeneity: Examine variation in differentiation efficiency

• Disease modeling applications:

  • Patient-specific iPSC-derived cardiomyocytes: Compare MYL2 expression/localization between control and disease lines

  • Variant effect assessment: Study impact of MYL2 mutations on protein stability and localization

  • Therapeutic response: Monitor MYL2 expression changes following experimental treatments

• Tissue engineering quality control:

  • Engineered heart tissue assessment: Use MYL2 staining to validate cardiomyocyte identity and organization

  • 3D culture analysis: Examine spatial distribution throughout engineered constructs

  • Mechanical conditioning effects: Study how mechanical forces influence MYL2 phosphorylation

• Direct reprogramming evaluation:

  • Fibroblast-to-cardiomyocyte conversion: Use MYL2 as late-stage conversion marker

  • Reprogramming efficiency: Quantify percentage of MYL2-positive cells

  • Functional maturation: Correlate MYL2 expression/organization with functional parameters

These approaches leverage the cardiac-specific expression of MYL2 to monitor differentiation status and functional maturity of developing cardiomyocytes .

What methodologies can effectively combine MYL2 localization studies with functional contractility measurements in cardiomyocyte models?

Integrating MYL2 localization with functional contractility assessment:

• Live-cell imaging approaches:

  • Fluorescently-tagged MYL2: Generate fusion constructs to monitor real-time localization

  • Calcium imaging correlation: Combine with calcium indicators to relate MYL2 dynamics to calcium transients

  • FRET-based tension sensors: Incorporate tension sensors into MYL2 to measure molecular forces

  • Traction force microscopy: Correlate MYL2 organization with cellular force generation

• Fixed-cell correlation methods:

  • Functional measurement followed by fixation: Record contractile parameters before immunostaining

  • Micropatterned substrates: Control cell geometry to standardize contractile measurements

  • Registration techniques: Align functional maps with immunofluorescence images

  • Computer vision analysis: Quantify sarcomere organization and correlate with function

• High-content screening platforms:

  • Automated imaging and analysis: Quantify MYL2 expression, localization, and sarcomere organization

  • Optical flow algorithms: Measure contractile parameters from brightfield imaging

  • Machine learning integration: Develop predictive models relating MYL2 patterns to function

  • Multi-parameter correlation: Identify relationships between multiple structural and functional variables

• Mutation-specific investigations:

  • Structure-function relationships: Compare localization patterns of wild-type vs. mutant MYL2

  • Contractile deficits: Link specific MYL2 mutations to functional impairments

  • Domain-specific effects: Determine how different domains affect localization and function

  • Rescue experiments: Test if contractile deficits can be restored by correcting MYL2 defects

• Phosphorylation-specific analyses:

  • State-specific antibodies: Use phospho-specific antibodies to relate phosphorylation to function

  • Kinase/phosphatase modulators: Experimentally alter phosphorylation state and measure functional consequences

  • Phosphomimetic mutations: Compare with phospho-null mutations to establish causality

• Advanced optical techniques:

  • Super-resolution microscopy: Resolve MYL2 localization at nanoscale resolution

  • FRAP (Fluorescence Recovery After Photobleaching): Measure MYL2 dynamics in living cells

  • Optogenetic approaches: Acutely modulate contractility while monitoring MYL2 localization

These integrated approaches can reveal how MYL2 mutations and post-translational modifications affect both localization and function, providing mechanistic insights into cardiomyopathies .

How can advanced imaging techniques and multi-antibody labeling strategies enhance research into MYL2's role in sarcomere assembly and maintenance?

Advanced imaging and multiplexed labeling approaches for MYL2 research:

• Super-resolution microscopy techniques:

  • STORM/PALM: Achieve 10-20 nm resolution to precisely localize MYL2 within sarcomeric structures

  • SIM: Obtain 100 nm resolution with conventional fluorophores for dynamic studies

  • Expansion microscopy: Physically expand specimens to resolve nanoscale organization

  • Application optimization: Adjust protocols for antibody penetration in expanded specimens

• Multi-epitope labeling strategies:

  • Co-localization panel: Combine MYL2 antibodies with markers for Z-discs, M-lines, and thin filaments

  • Temporal assembly markers: Label proteins incorporated at different stages of sarcomere assembly

  • Domain-specific antibodies: Use antibodies targeting different MYL2 domains to reveal protein orientation

  • Phosphorylation-specific detection: Include phospho-Ser18 specific antibodies to monitor regulatory state

• Volumetric imaging approaches:

  • 3D confocal microscopy: Reconstruct sarcomere architecture throughout the cell volume

  • Light-sheet microscopy: Capture MYL2 organization in whole engineered tissues with minimal photobleaching

  • Tissue clearing techniques: Apply CLARITY, CUBIC, or other clearing methods for deep tissue imaging

  • 3D electron microscopy: Correlate with immunogold labeling for ultrastructural localization

• Live imaging innovations:

  • Fluorescent protein fusions: Generate knock-in lines expressing MYL2-FP fusions

  • Split fluorescent protein complementation: Visualize MYL2 interactions with binding partners

  • Optogenetic perturbation: Combine with light-controlled disruption of sarcomere components

  • Long-term imaging: Monitor sarcomere assembly, maintenance, and turnover over days

• Correlative microscopy approaches:

  • CLEM (Correlative Light and Electron Microscopy): Relate MYL2 immunofluorescence to ultrastructure

  • Functional imaging correlation: Link MYL2 organization to contractile parameters

  • Force measurement integration: Correlate MYL2 patterns with traction force microscopy

  • Multi-scale imaging: Connect molecular, cellular, and tissue-level observations

• Quantitative analysis frameworks:

  • Sarcomere organization metrics: Measure Z-disc spacing, A-band width, and sarcomere regularity

  • Colocalization analysis: Quantify spatial relationships between MYL2 and other sarcomeric proteins

  • Temporal dynamics: Track assembly/disassembly rates during development or stress responses

  • Machine learning classification: Develop automated pattern recognition for sarcomere phenotyping

These advanced approaches enable researchers to connect MYL2 molecular characteristics to higher-order structural organization and function in both normal physiology and disease states .

What are emerging opportunities for using MYL2 antibodies in the development of cardiac disease biomarkers?

Emerging opportunities for MYL2-based cardiac biomarker development:

• Post-translational modification profiling:

  • Phosphorylation state analysis: Use phospho-specific antibodies to detect disease-specific phosphorylation patterns

  • PTM combinations: Develop antibodies recognizing specific combinations of modifications

  • Modification quantification: Establish ratiometric measurements of modified vs. unmodified MYL2

  • Circulating MYL2 detection: Develop high-sensitivity assays for serum/plasma MYL2 forms

• Mutation-specific diagnostic development:

  • Variant-specific antibodies: Generate antibodies that selectively recognize common MYL2 mutations

  • Conformational antibodies: Develop antibodies recognizing disease-specific protein conformations

  • Stability assessments: Quantify mutant protein levels as diagnostic indicators

  • Expression level profiling: Monitor altered MYL2 levels in heart failure (69% of control levels)

• Single-cell diagnostic applications:

  • Cardiomyocyte phenotyping: Classify individual cells based on MYL2 expression patterns

  • Spatial proteomics: Map MYL2 distribution changes in tissue sections from diseased hearts

  • Heterogeneity quantification: Measure cell-to-cell variation in MYL2 expression/localization

  • Digital pathology integration: Develop automated image analysis algorithms for IHC/IF quantification

• Multiparameter biomarker panels:

  • Combinatorial profiles: Integrate MYL2 with other cardiac markers for improved specificity

  • Machine learning classification: Develop predictive models based on multiple marker patterns

  • Risk stratification: Correlate MYL2 patterns with clinical outcomes

  • Treatment response monitoring: Track changes in MYL2 parameters during therapeutic interventions

• Point-of-care testing development:

  • Rapid immunoassays: Develop lateral flow or microfluidic platforms for MYL2 detection

  • Automated image analysis: Create portable systems for quantitative IHC/IF interpretation

  • Minimally invasive sampling: Explore detection in peripheral blood or other accessible samples

  • Digital connectivity: Link testing platforms with electronic health records and decision support

• Therapeutic monitoring applications:

  • Treatment efficacy assessment: Monitor normalization of MYL2 expression/localization

  • Drug response prediction: Correlate baseline MYL2 patterns with therapeutic outcomes

  • Cardiotoxicity detection: Use MYL2 alterations as early indicators of drug-induced cardiac damage

  • Regenerative medicine evaluation: Track MYL2 expression in transplanted cells/engineered tissues