YPR170W-B Antibody

What is YPR170W-B and why is it significant in V-ATPase research?

YPR170W-B is a membrane-embedded component of the VO motor complex in V-ATPases found in Saccharomyces cerevisiae. It has been tentatively identified as subunit f of the V-ATPase . This protein was confirmed as a component of the VO complex through affinity purification experiments using a 3×FLAG-tag fused to its C-terminus . Unlike some other V-ATPase components, YPR170W-B deletion does not produce the conditionally lethal VMA phenotype, indicating it is not essential for V-ATPase localization or proton pumping activity . Its peripheral location in the complex suggests a role that is separate from the core proton transport mechanism, making it an interesting target for studying auxiliary functions of the V-ATPase complex.

How can YPR170W-B antibodies be validated for specificity in yeast studies?

Validation of YPR170W-B antibodies requires a multi-faceted approach:

• Knockout validation: Using strains with YPR170W-B deletion (such as strain MMJY1 created by deleting YPR170W-B in strain CACY1 via homologous recombination with the NatR cassette) to confirm absence of signal.

• Tag-based validation: Comparing antibody detection with tagged versions of the protein (e.g., with 3×FLAG-tag as described in the literature) .

• Mass spectrometry correlation: Confirming that the protein detected by the antibody corresponds to the same mass and peptide fragments identified in LC-MS/MS analyses of purified VO complexes .

• Western blot analysis: Examining band patterns in wild-type vs. modified strains, with expected molecular weight corresponding to YPR170W-B (approximately 8.5 kDa).

What expression systems are optimal for generating YPR170W-B antibodies?

For YPR170W-B antibody production, consider these expression systems:

How should researchers design experiments to study YPR170W-B interactions with other V-ATPase components?

When investigating YPR170W-B interactions with other V-ATPase components, implement a comprehensive strategy:

• Co-immunoprecipitation (Co-IP): Utilize YPR170W-B antibodies for pulldown experiments, followed by western blotting or mass spectrometry to identify interacting partners. This approach successfully identified associations between YPR170W-B and other VO complex components .

• Proximity labeling approaches: Consider BioID or APEX2 fusion proteins to identify transient or weak interactions not captured by traditional Co-IP.

• Crosslinking mass spectrometry: Apply protein crosslinkers before immunoprecipitation to capture dynamic interactions within the V-ATPase complex.

• Fluorescence microscopy: Implement dual-labeling experiments using YPR170W-B antibodies alongside antibodies against known V-ATPase components to assess co-localization patterns.

• Mutation analysis: Introduce specific mutations in YPR170W-B and assess changes in interaction patterns using antibody-based detection methods.

The experimental design should account for the membrane-embedded nature of YPR170W-B, requiring appropriate detergent conditions for solubilization while preserving protein-protein interactions.

What are the optimal fixation and permeabilization protocols for immunolocalization of YPR170W-B?

For successful immunolocalization of YPR170W-B, consider these protocol recommendations:

• Fixation options:

  • Paraformaldehyde (4%, 15-20 minutes) preserves protein structure while maintaining accessibility

  • Methanol fixation (-20°C, 10 minutes) may provide better access to membrane proteins

  • Dual fixation with glutaraldehyde (0.1-0.5%) improves membrane protein retention

• Permeabilization considerations:

  • For yeast cells, use spheroplast preparation with zymolyase (1mg/ml, 30 minutes at 30°C)

  • Follow with 0.1-0.5% Triton X-100 or 0.1% saponin for membrane permeabilization

  • Digitonin (10-50μg/ml) provides gentler permeabilization to preserve membrane structures

• Blocking recommendations:

  • 3-5% BSA or normal serum from the same species as secondary antibody

  • Add 0.1% Tween-20 to reduce nonspecific binding

  • Include 5-10mM glycine to quench remaining aldehydes from fixation

• Antigen retrieval:

  • Consider citrate buffer (pH 6.0) heating for formalin-fixed samples

  • Enzymatic treatment with proteinase K may improve access to membrane epitopes

Optimize these conditions based on the specific YPR170W-B antibody characteristics and sample preparation methods.

How can YPR170W-B antibodies contribute to studying V-ATPase assembly mechanisms?

YPR170W-B antibodies offer valuable tools for investigating V-ATPase assembly through multiple approaches:

• Temporal assembly studies: Using YPR170W-B antibodies in pulse-chase experiments can reveal when this subunit incorporates into the assembling complex. Since YPR170W-B is not essential for V-ATPase localization or proton pumping , tracking its incorporation may provide insights into auxiliary assembly pathways.

• Structural analysis checkpoints: Apply YPR170W-B antibodies to detect partially assembled intermediates during V-ATPase biogenesis, potentially identifying assembly checkpoints.

• Assembly factor interactions: Use YPR170W-B antibodies in immunoprecipitation studies coupled with mass spectrometry to identify transient interaction partners that may function as assembly chaperones.

• Mutant analysis: Apply YPR170W-B antibodies to assess assembly status in various V-ATPase mutant backgrounds, particularly those affecting peripheral components.

• Subcellular tracking: Employ YPR170W-B antibodies alongside markers for cellular compartments to trace the trafficking pathway of this subunit from synthesis to final incorporation.

The peripheral position of YPR170W-B in the V-ATPase complex, as revealed by cryo-EM studies , suggests it may be added later in the assembly process, making it a potentially valuable marker for late-stage assembly events.

What are the methodological considerations for using YPR170W-B antibodies in cryo-EM structural studies?

When incorporating YPR170W-B antibodies into cryo-EM structural investigations:

• Fab fragment preparation: Convert YPR170W-B antibodies to Fab fragments through controlled proteolytic digestion to minimize flexibility and size while maintaining binding specificity.

• Antibody labeling strategies:

  • Direct gold nanoparticle conjugation for visualization of antibody binding sites

  • Use bifunctional crosslinkers with minimal spacer arms for controlled antibody-protein distance

• Sample stability considerations:

  • Assess complex stability with and without antibody binding through thermal shift assays

  • Optimize buffer conditions to maintain native membrane protein structure with bound antibody

• Grid preparation optimization:

  • Test multiple detergent concentrations to balance micelle size with antibody accessibility

  • Consider nanodiscs or amphipols as alternatives to detergent for membrane protein stabilization

• Data processing strategies:

  • Implement masked classification approaches to address potential flexibility introduced by antibody binding

  • Use local refinement techniques focused on regions of interest identified by antibody labeling

Recent cryo-EM studies successfully mapped YPR170W-B location in the VO complex by comparing wild-type complexes with those purified from YPR170W-B deletion strains , demonstrating the potential for antibody-based approaches to further define structural details.

How can researchers address common challenges in detecting YPR170W-B in complex biological samples?

When facing difficulties detecting YPR170W-B:

• Sample preparation optimization:

  • Enhance membrane protein extraction using specialized detergents (DDM, CHAPS, or digitonin)

  • Implement sequential extraction protocols to enrich membrane fractions

  • Consider using specialized membrane protein extraction kits

• Signal enhancement strategies:

  • Amplify signal using tyramide signal amplification (TSA) for immunodetection

  • Employ biotin-streptavidin systems for increased sensitivity

  • Consider multiple-epitope detection using antibody cocktails against different regions of YPR170W-B

• Interference minimization:

  • Implement additional washing steps with increased detergent concentrations

  • Use specialized blocking agents for membrane protein work

  • Consider low-binding microplates and tubes to minimize protein loss

• Advanced detection methods:

  • Apply proximity ligation assays (PLA) for detecting low-abundance YPR170W-B in context

  • Consider mass cytometry (CyTOF) for multiplexed detection alongside other V-ATPase components

  • Implement super-resolution microscopy techniques for precise localization

Research has shown that YPR170W-B can be successfully detected and localized through affinity purification approaches using C-terminal tags , which may inform antibody-based detection strategies.

How should contradictory results between YPR170W-B antibody data and genetic analyses be reconciled?

When faced with discrepancies between antibody-based results and genetic analyses:

• Antibody validation reassessment:

  • Confirm specificity using knockout controls and peptide competition assays

  • Evaluate epitope accessibility in different experimental conditions

  • Test multiple antibodies targeting different epitopes of YPR170W-B

• Genetic compensation consideration:

  • Investigate potential upregulation of functionally related proteins in YPR170W-B deletion strains

  • Implement acute protein depletion (e.g., auxin-inducible degrons) alongside chronic deletion models

  • Consider double knockout approaches to identify redundant systems

• Technical validation:

  • Apply orthogonal techniques (mass spectrometry, RNA sequencing) to validate antibody findings

  • Implement quantitative approaches like qPCR and targeted proteomics

  • Consider differences between protein levels (antibody detection) and function (genetic analysis)

• Phenotypic assessment:

  • Conduct detailed phenotypic analysis under various stress conditions

  • Investigate subtle phenotypes that might be masked under standard growth conditions

  • Implement high-throughput screening approaches to identify conditional phenotypes

Published research has shown that YPR170W-B deletion does not produce the VMA phenotype , suggesting functional redundancy or context-dependent roles that might explain discrepancies between antibody detection and phenotypic observations.

What emerging technologies could enhance YPR170W-B antibody applications in structural biology?

Cutting-edge technologies for YPR170W-B antibody applications include:

• Single-particle cryo-EM with antibody fiducials:

  • Strategic antibody labeling at key positions to resolve ambiguous densities

  • Leveraging antibody-induced conformational changes to capture transition states

  • Combining with locally focused refinement techniques for high-resolution structure determination

• Integrative structural biology approaches:

  • Combining cryo-EM with mass spectrometry-based crosslinking

  • Correlative light and electron microscopy (CLEM) using fluorescently labeled antibodies

  • Hybrid modeling incorporating antibody-based constraints

• Time-resolved structural studies:

  • Time-resolved cryoEM with antibody-based triggering of conformational changes

  • Temperature-jump approaches combined with antibody labeling

  • Microfluidic mixing devices for capturing transient states

• In situ structural biology:

  • Focused ion beam milling of cellular samples with antibody labeling

  • Cryo-electron tomography with antibody fiducials for in-cell localization

  • Correlative approaches linking antibody-based light microscopy with electron tomography

The successful determination of YPR170W-B's position in the V-ATPase complex through comparative cryo-EM of wild-type and deletion strains demonstrates the potential for antibody-enhanced structural approaches to further refine our understanding of this protein's interactions and functions.