Recombinant Human V-type proton ATPase subunit S1-like protein (ATP6AP1L)

What is ATP6AP1L and how does it differ from ATP6AP1?

ATP6AP1L (ATPase H+ transporting accessory protein 1 like) is a pseudogene located on chromosome 5 that encodes a protein subunit of the vacuolar proton pump . Despite being annotated as a pseudogene, functional studies have demonstrated that ATP6AP1L produces a protein that plays significant roles in cellular processes.

The full-length ATP6AP1L protein consists of 224 amino acids with a characteristic transmembrane domain and several conserved functional motifs that facilitate its interaction with other proteins in the V-type ATPase complex .

What are the known expression patterns of ATP6AP1L in normal tissues and cancer?

ATP6AP1L expression varies across normal human tissues, with differential expression patterns that suggest tissue-specific functions. In cancer tissues, particularly breast cancer, altered expression of ATP6AP1L has been observed. Research has shown that downregulation of ATP6AP1L correlates with breast cancer risk and poor prognosis in patients .

Unlike its related protein ATP6AP1, which shows significant upregulation in colorectal cancer , ATP6AP1L typically demonstrates reduced expression in breast cancer tissues. This expression pattern supports its potential role as a tumor suppressor in breast cancer.

To properly study ATP6AP1L expression across tissues, researchers typically employ quantitative PCR, western blotting, and immunohistochemistry methods, with careful selection of specific antibodies that can distinguish between ATP6AP1L and the structurally similar ATP6AP1.

What genetic variations impact ATP6AP1L expression and function?

A significant genetic variant affecting ATP6AP1L expression is rs10514231, located in the second intron of the ATG10 gene. This SNP has been identified as a regulatory variant that influences ATP6AP1L expression levels .

Mechanistically, the T allele of rs10514231 leads to ATP6AP1L downregulation by decreasing the binding affinity of the transcription factor TCF7L2 . This regulatory mechanism provides a molecular explanation for how this genetic variant influences breast cancer susceptibility.

Researchers investigating genetic variations affecting ATP6AP1L should consider:

• Conducting allele-specific reporter gene assays to verify regulatory effects

• Performing chromatin immunoprecipitation (ChIP) to confirm transcription factor binding differences

• Utilizing CRISPR-based approaches to model the effects of specific variants on gene expression

How do epigenetic mechanisms regulate ATP6AP1L expression?

While the search results don't explicitly address epigenetic regulation of ATP6AP1L, studies on related proteins suggest potential regulatory mechanisms worth investigating:

• DNA methylation analysis of the ATP6AP1L promoter region can reveal cancer-specific epigenetic alterations

• Histone modification patterns may influence accessibility of transcription factors to ATP6AP1L regulatory regions

• Non-coding RNAs might target ATP6AP1L mRNA, affecting post-transcriptional regulation

Research methodologies for investigating epigenetic regulation include:

• Bisulfite sequencing for DNA methylation analysis

• ChIP-seq for histone modification profiling

• RNA-seq combined with bioinformatic analysis to identify potential miRNA regulators

What is the mechanistic role of ATP6AP1L in breast cancer progression?

ATP6AP1L appears to function as a tumor suppressor in breast cancer. Overexpression of the ATP6AP1L gene in cancer cells has been shown to diminish cell proliferation, migration, and invasion capabilities . Conversely, downregulation of ATP6AP1L correlates with breast cancer risk and poor prognosis in patients .

The molecular mechanisms underlying this tumor-suppressive function may involve:

• Regulation of vacuolar acidification processes

• Modulation of autophagy pathways

• Influence on cellular signaling cascades that control proliferation and migration

To investigate these mechanisms, researchers should consider:

• Conducting gain and loss of function experiments using overexpression constructs and siRNA/shRNA

• Analyzing downstream signaling pathways using phosphoproteomic approaches

• Assessing changes in cellular phenotypes through proliferation, migration, and invasion assays

How does ATP6AP1L interact with the TCF7L2 pathway in cancer?

The T allele of rs10514231 leads to ATP6AP1L downregulation by decreasing the binding affinity of TCF7L2 . This interaction with the TCF7L2 pathway provides insight into how ATP6AP1L is regulated in cancer contexts.

TCF7L2 is a key transcription factor in the Wnt/β-catenin signaling pathway, which plays crucial roles in cell proliferation, differentiation, and cancer development. The functional interaction between ATP6AP1L and TCF7L2 suggests that ATP6AP1L may be integrated within broader signaling networks that influence cancer progression.

Researchers interested in this interaction should:

• Perform co-immunoprecipitation experiments to confirm physical interactions

• Use luciferase reporter assays to quantify transcriptional effects

• Employ ChIP-seq to map genome-wide binding patterns of TCF7L2 in relation to ATP6AP1L regulation

What are the optimal conditions for expressing and purifying recombinant ATP6AP1L?

For successful expression and purification of recombinant ATP6AP1L, researchers should consider the following parameters:

• Expression system: E. coli expression systems have been successfully used to produce full-length ATP6AP1L protein .

• Protein tags: N-terminal 10xHis-tagged constructs can facilitate purification while maintaining protein functionality .

• Buffer conditions: Tris/PBS-based buffers with 6% Trehalose at pH 8.0 provide suitable conditions for protein stability .

• Storage considerations: Store at -20°C/-80°C upon receipt, with aliquoting necessary for multiple use to avoid repeated freeze-thaw cycles that may compromise protein integrity .

• Expression optimization: Consider codon optimization for the expression system and test multiple induction conditions to maximize protein yield.

What cell-based assays are most informative for studying ATP6AP1L function?

To comprehensively analyze ATP6AP1L function in cellular contexts, researchers should consider these methodological approaches:

• Cell proliferation assays: MTT, BrdU incorporation, or real-time cell analysis systems can quantify how ATP6AP1L affects proliferation rates.

• Migration and invasion assays: Transwell, wound healing, and Boyden chamber assays can assess the impact of ATP6AP1L on cancer cell motility and invasiveness.

• Protein localization studies: Immunofluorescence microscopy with subcellular markers can determine the precise localization of ATP6AP1L within cells.

• Protein-protein interaction studies: Co-immunoprecipitation, proximity ligation assays, or FRET can identify binding partners of ATP6AP1L.

• Functional genomics: CRISPR-Cas9 mediated knockout or knockdown approaches using siRNA/shRNA can reveal the consequences of ATP6AP1L loss.

Research has demonstrated that overexpression of ATP6AP1L in cancer cells diminishes cell proliferation, migration, and invasion capabilities , suggesting that these assays are particularly informative for studying its function.

How does ATP6AP1L influence immune cell infiltration in the tumor microenvironment?

While direct evidence for ATP6AP1L's role in immune regulation is limited in the provided search results, we can draw partial insights from studies on the related protein ATP6AP1:

ATP6AP1 expression has been correlated with immune cell infiltration in colorectal cancer, including specific relationships with B cells, T cells, macrophages, and regulatory T cells . By analogy, ATP6AP1L may exert similar influences on the tumor immune microenvironment in breast cancer.

Researchers investigating this aspect should:

• Perform immunohistochemical analysis of tumor tissues to correlate ATP6AP1L expression with immune cell markers

• Use flow cytometry to quantify immune cell populations in ATP6AP1L-manipulated tumor models

• Analyze cytokine and chemokine profiles in response to ATP6AP1L modulation

• Investigate potential direct interactions between ATP6AP1L and immune regulatory pathways

What is the relationship between ATP6AP1L and autophagy pathways in cancer?

The genetic variant rs10514231, which affects ATP6AP1L expression, is located in the second intron of ATG10, an autophagy-related gene . This genomic proximity suggests a potential functional relationship between ATP6AP1L and autophagy pathways.

Autophagy plays complex roles in cancer, functioning as both a tumor suppressor mechanism in early stages and a survival mechanism for established tumors. The connection between ATP6AP1L and ATG10 warrants investigation into how ATP6AP1L might influence autophagy processes in cancer cells.

Methodological approaches for studying this relationship include:

• Autophagy flux assays using LC3 puncta formation and p62 degradation

• Electron microscopy to visualize autophagic structures

• Co-expression analysis of ATP6AP1L with key autophagy regulators

• Functional assays assessing autophagic responses under various stresses when ATP6AP1L is modulated

How can ATP6AP1L expression be utilized as a prognostic biomarker?

ATP6AP1L downregulation correlates with breast cancer risk and poor prognosis in patients , suggesting its potential utility as a prognostic biomarker. To develop ATP6AP1L as a clinical biomarker, researchers should:

• Conduct large-scale retrospective analyses correlating ATP6AP1L expression with patient outcomes across different cancer subtypes

• Establish standardized quantification methods for ATP6AP1L expression in clinical samples

• Determine optimal cutoff values for stratifying patients into risk groups

• Integrate ATP6AP1L expression with other established biomarkers to improve prognostic accuracy

• Validate findings in prospective clinical cohorts

The development of immunohistochemistry-based detection methods with specific antibodies would facilitate the translation of ATP6AP1L as a biomarker into clinical practice.

What therapeutic strategies could target ATP6AP1L or its regulatory pathways?

Based on its tumor-suppressive properties in breast cancer, several therapeutic approaches targeting ATP6AP1L or its regulatory pathways could be considered:

• Gene therapy approaches to restore ATP6AP1L expression in tumors where it is downregulated

• Small molecule modulators of the TCF7L2-ATP6AP1L regulatory axis

• Development of synthetic peptides mimicking ATP6AP1L functional domains

• Combination therapies targeting both ATP6AP1L and related signaling pathways

• Immunotherapeutic approaches leveraging ATP6AP1L's relationships with immune cell populations

Researchers should focus on high-throughput screening methods to identify compounds that can modulate ATP6AP1L expression or function, followed by detailed mechanistic studies and preclinical validation in appropriate cancer models.

How do ATP6AP1L and ATP6AP1 functionally differ in various cancer contexts?

While ATP6AP1L appears to function as a tumor suppressor in breast cancer , ATP6AP1 is upregulated in colorectal cancer and associated with poor prognosis . This contrasting expression pattern and functional role warrant comparative investigations.

Key research approaches should include:

• Parallel analysis of both proteins across multiple cancer types using tissue microarrays

• Comparative functional studies with simultaneous manipulation of both genes

• Domain-specific analysis to identify structural determinants of their distinct functions

• Pathway enrichment analysis to map their involvement in shared and unique signaling networks

Understanding the functional divergence between these related proteins could provide deeper insights into tissue-specific roles of V-type ATPases in cancer biology.

What are the systems biology approaches to understand ATP6AP1L in cellular homeostasis?

To comprehensively understand ATP6AP1L's role in cellular homeostasis, researchers should employ integrative systems biology approaches:

• Multi-omics integration combining:

  • Transcriptomics (RNA-seq) to identify gene expression networks

  • Proteomics to map protein interaction networks

  • Metabolomics to assess impacts on cellular metabolism

  • Phosphoproteomics to elucidate signaling cascades

• Network analysis tools to identify:

  • Hub genes connecting ATP6AP1L to broader cellular pathways

  • Feedback and feedforward regulatory loops

  • Pathway cross-talk mechanisms

• Mathematical modeling approaches:

  • Ordinary differential equation models of ATP6AP1L-involved pathways

  • Agent-based models of cell population dynamics

  • Machine learning approaches to predict regulatory relationships

These integrative approaches would provide a comprehensive understanding of ATP6AP1L's role within the complex cellular networks governing cancer development and progression.