MPZL1 Human

What is MPZL1 and what characterizes its molecular structure?

Myelin protein zero-like protein 1 (MPZL1) is encoded by the MPZL1 gene and functions as a single-pass type I membrane protein. It contains an extracellular domain, a transmembrane region, and a cytoplasmic portion that mediates signal transduction. The human MPZL1 protein spans from Ser36 to Val162 in its mature form and has a molecular weight ranging from 20-28 kDa under reducing conditions . The protein's structure enables it to function as a cell surface receptor involved in various signaling cascades. When studying MPZL1 structure, researchers typically employ techniques such as Western blotting with reducing SDS-PAGE to confirm the molecular weight and protein characterization.

What is the expression pattern of MPZL1 in human tissues?

MPZL1 displays a widespread expression pattern throughout human tissues, with notably higher expression levels detected in the heart, placenta, kidney, and pancreas . This differential expression pattern suggests tissue-specific roles for this protein. When investigating MPZL1 expression, researchers should consider the following methodological approach:

• Use RT-qPCR to quantify MPZL1 mRNA levels across different tissues

• Employ immunohistochemistry with anti-MPZL1 antibodies for spatial localization

• Validate findings with Western blot analysis of tissue lysates

• Compare expression between normal and pathological tissue samples

In pathological contexts, aberrant MPZL1 expression has been documented in various cancer types, including lung adenocarcinoma and gallbladder carcinoma, indicating its potential role in disease progression .

How does MPZL1 participate in cellular signaling pathways?

MPZL1 functions as a central mediator in several signaling cascades, with its primary mechanism involving the recruitment of PTPN11/SHP-2 phosphatase to the cell membrane. This recruitment subsequently leads to the activation and phosphorylation of Src kinase at Tyr426, triggering downstream effects including cortactin phosphorylation . This signaling axis plays a critical role in promoting cell migration, particularly in hepatocellular carcinoma (HCC) cells.

For researchers investigating MPZL1 signaling, the following experimental approach is recommended:

• Perform co-immunoprecipitation assays to detect protein-protein interactions

• Use phospho-specific antibodies to monitor phosphorylation events

• Employ kinase inhibitors to validate pathway dependencies

• Utilize siRNA knockdown or CRISPR-Cas9 gene editing to assess pathway perturbations

Understanding these signaling mechanisms provides insights into how MPZL1 contributes to both normal cellular functions and pathological processes.

What methods are most effective for studying MPZL1 protein-protein interactions?

When investigating MPZL1 protein-protein interactions, researchers should employ a multi-faceted approach that combines both in vitro and cellular techniques:

• Co-immunoprecipitation followed by mass spectrometry to identify novel binding partners

• Proximity ligation assays to visualize interactions in intact cells

• FRET or BRET analysis for real-time monitoring of protein interactions

• Yeast two-hybrid screening for initial identification of potential interactors

• GST pull-down assays with recombinant proteins to confirm direct interactions

These methodologies help elucidate how MPZL1 interacts with partners such as PTPN11/SHP-2 and Src family kinases. A particularly important interaction is MPZL1's role as a major receptor for concanavalin-A (ConA), participating in ConA-induced cellular signaling cascades that include Src family tyrosine-protein kinases . These interactions form the molecular basis for MPZL1's functions in various cellular processes, including migration and proliferation.

How does MPZL1 contribute to cancer progression in different tumor types?

MPZL1 has emerged as a significant contributor to cancer progression across multiple tumor types. In lung adenocarcinoma (LUAD), MPZL1 upregulation promotes tumor proliferation, invasion, and migration while suppressing immune function . Similarly, in gallbladder carcinoma, high MPZL1 expression correlates with advanced disease stages .

The mechanisms through which MPZL1 promotes oncogenesis include:

• Enhanced cell proliferation and clonal expansion

• Increased cellular migration and invasion capabilities

• Activation of the TGF-β1 signaling pathway

• Immunosuppressive effects, particularly on CD8+ T cell infiltration

For researchers studying MPZL1 in cancer, experimental approaches should include:

• Patient tissue analysis with immunohistochemistry to correlate expression with clinical outcomes

• MPZL1 knockdown and overexpression in cancer cell lines to assess functional impacts

• In vivo xenograft models to evaluate tumor growth and metastasis

• Single-cell RNA sequencing to understand heterogeneous expression within tumor microenvironments

Importantly, studies have demonstrated that silencing MPZL1 inhibits cell proliferation, clone formation, and tumor growth, while overexpression produces opposite effects . This suggests MPZL1 as a potential therapeutic target in cancer treatment strategies.

What methodologies are optimal for investigating MPZL1 regulation of cell migration?

To thoroughly investigate MPZL1's role in cell migration, researchers should implement a comprehensive experimental approach:

• Wound healing (scratch) assays with time-lapse microscopy

• Transwell migration and invasion assays with extracellular matrix components

• 3D spheroid invasion assays to better mimic in vivo conditions

• Live-cell imaging with fluorescently tagged MPZL1 to track subcellular localization during migration

• Rho GTPase activation assays to assess cytoskeletal regulation

When designing these experiments, consideration should be given to:

• Developing stable MPZL1 knockdown or overexpression cell lines

• Using phosphomimetic and phosphorylation-deficient MPZL1 mutants

• Employing specific inhibitors of downstream pathways (Src inhibitors, SHP-2 inhibitors)

• Quantifying cortactin phosphorylation as a downstream readout

MPZL1 has been shown to recruit PTPN11/SHP-2 to the cell membrane and subsequently activate/phosphorylate Src kinase at Tyr426, which promotes phosphorylation of cortactin and migration of hepatocellular carcinoma cells . This mechanistic understanding provides researchers with specific molecular events to target in their experimental designs.

How does MPZL1 interact with the TGF-β1 signaling pathway in disease progression?

The interaction between MPZL1 and the transforming growth factor-β1 (TGF-β1) signaling pathway represents a critical mechanism in disease progression, particularly in lung adenocarcinoma . To effectively study this interaction, researchers should:

• Perform co-immunoprecipitation assays to detect physical interactions between MPZL1 and TGF-β pathway components

• Analyze phosphorylation of Smad proteins in the context of MPZL1 manipulation

• Use chromatin immunoprecipitation (ChIP) to identify transcriptional regulatory mechanisms

• Employ dual-luciferase reporter assays to quantify TGF-β pathway activation

• Conduct RNA-seq analysis to identify gene expression changes related to epithelial-mesenchymal transition

Research findings indicate that MPZL1 combines with TGF-β1 to promote lung adenocarcinoma progression . This synergistic effect suggests that targeting both pathways simultaneously may provide enhanced therapeutic benefits. When designing experiments to investigate this interaction, researchers should include appropriate controls and consider the temporal dynamics of signaling events.

What is the relationship between MPZL1 expression and immune cell infiltration in the tumor microenvironment?

The relationship between MPZL1 expression and immune cell infiltration represents an emerging area of research with significant implications for cancer immunotherapy. Studies have revealed that high expression of MPZL1 negatively correlates with CD8+ T cell infiltration in tumor tissues and may contribute to immunotherapy resistance .

To investigate this relationship, researchers should employ:

• Multiplex immunofluorescence imaging of tumor tissues to simultaneously visualize MPZL1 expression and immune cell markers

• Flow cytometric analysis of tumor-infiltrating lymphocytes in models with MPZL1 manipulation

• Single-cell RNA sequencing to characterize immune cell populations and their states

• Immune checkpoint expression analysis in relation to MPZL1 levels

• In vivo models combining MPZL1 modulation with immune checkpoint inhibitor treatment

The negative correlation between MPZL1 expression and CD8+ T cell infiltration suggests that MPZL1 may contribute to an immunosuppressive tumor microenvironment . This finding has important implications for immunotherapy response prediction and potential combination therapy approaches.

What are effective approaches for modulating MPZL1 expression in experimental settings?

Modulating MPZL1 expression is essential for studying its functional roles. Based on the literature, several effective approaches can be employed:

RNA Interference (RNAi) Approach:

Three pairs of small interfering RNA (siRNA) probes targeting MPZL1 mRNA can be designed and tested for efficiency. Researchers should select the most effective siRNA for silencing MPZL1 expression . This approach allows for transient knockdown of MPZL1.

Overexpression Approach:

• Extract total RNA from normal tissue using TRIzol®

• Perform reverse transcription to obtain cDNA

• Amplify the MPZL1 gene with primers containing appropriate restriction sites

• Clone the amplified cDNA into an expression vector (e.g., pCMV)

• Verify the construct by sequencing

• Transfect target cells with the verified construct

CRISPR-Cas9 Gene Editing:

For stable genetic manipulation, CRISPR-Cas9 technology offers advantages over transient approaches. Design guide RNAs targeting the MPZL1 locus and screen for effective knockout or knock-in clones.

Inducible Expression Systems:

When studying dose-dependent or temporal effects, researchers can employ tetracycline-inducible or similar systems to achieve controlled MPZL1 expression.

These approaches provide versatile tools for investigating MPZL1 function across various experimental contexts, from cell culture models to in vivo systems.

How can MPZL1 be effectively targeted for potential therapeutic applications?

Given MPZL1's role in promoting cancer progression through multiple mechanisms, targeting this protein represents a promising therapeutic strategy. Several approaches warrant investigation:

• Small molecule inhibitors targeting MPZL1's protein-protein interactions

• Monoclonal antibodies against the extracellular domain to block signaling

• Antisense oligonucleotides or siRNA-based therapeutics for expression knockdown

• Peptide mimetics that disrupt specific MPZL1 interactions

• Combination approaches targeting both MPZL1 and associated pathways (TGF-β, Src)

When developing MPZL1-targeted therapeutics, researchers should consider:

• Tissue-specific expression patterns to minimize off-target effects

• Optimal delivery methods based on chemical properties

• Biomarkers for patient stratification

• Resistance mechanisms that might emerge

Pre-clinical studies have demonstrated that silencing MPZL1 inhibits tumor cell proliferation and growth , suggesting that therapeutic approaches aimed at reducing MPZL1 expression or activity could be effective in cancer treatment.

What are the key considerations for analyzing MPZL1 in patient samples?

When analyzing MPZL1 in patient samples, researchers should address several critical methodological considerations:

• Sample Collection and Processing:

  • Fresh frozen versus formalin-fixed paraffin-embedded tissue considerations

  • Timing between tissue collection and fixation to preserve protein integrity

  • Standardized protocols for sample handling to ensure reproducibility

• Detection Methods:

  • Immunohistochemistry (IHC) with validated antibodies

  • Quantitative scoring systems for expression levels

  • RNA-based methods (RT-qPCR, RNA-seq) for transcript analysis

  • Protein-based methods (Western blot, ELISA) for quantitative assessment

• Interpretation and Scoring:

  • Define clear thresholds for positive staining (e.g., ≥5% nuclear positivity)

  • Employ multiple independent observers for unbiased assessment

  • Use digital pathology tools for quantitative analysis when possible

• Clinical Correlation:

  • Collect comprehensive clinical data to correlate with MPZL1 expression

  • Consider multivariate analysis to account for confounding factors

  • Evaluate both primary and metastatic lesions when available

These methodological considerations are essential for generating reliable and clinically relevant data regarding MPZL1 expression and its implications in patient outcomes.

What are the emerging research directions for MPZL1 beyond current applications?

The study of MPZL1 is evolving rapidly, with several promising research directions emerging:

• Single-cell Analysis: Investigating MPZL1 expression and function at the single-cell level will provide insights into cellular heterogeneity within tissues and tumors.

• Structural Biology: Determining the three-dimensional structure of MPZL1 and its complexes will facilitate structure-based drug design approaches.

• Systems Biology: Integrating MPZL1 into broader signaling networks will help understand its context-dependent functions and identify key regulatory nodes.

• Biomarker Development: Evaluating MPZL1 as a prognostic or predictive biomarker, particularly for immunotherapy response in cancers.

• Therapeutic Targeting: Developing novel strategies to selectively modulate MPZL1 activity in disease contexts.

• Immune Regulation: Further exploring the relationship between MPZL1 and immune cell function, particularly in the context of cancer immunotherapy.