Co-IP and RPPA Method for Protein Interaction Analysis

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Solution Overview

Problem

Current methods for identifying protein-protein interactions (PPI) are labor-intensive, not conducive to high-throughput analysis, and require large cell quantities, making them challenging for clinical tissue samples with limited cellular amounts.

Innovation Solution

A novel method combining Co-immunoprecipitation (Co-IP) with Reverse Phase Protein Array (RPPA) for high-throughput, sensitive, and multiplexed analysis of protein complexes, allowing for the identification of activated members of protein complexes from small sample inputs, known as the Multinodal Protein Interactome Network Array (MPINA).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mass spectrometry is used to identify protein complexes, then comprehensive protein identification is achieved, but millions to billions of cells are required as input

Engineering Contradiction:
Improveprotein identification accuracyVSAvoidcell quantity required
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The method segments the protein complex identification process into two distinct stages: (1) Co-immunoprecipitation to isolate and concentrate the protein complex of interest from the cellular lysate, and (2) RPPA to detect and quantify multiple proteins within the isolated complex. This segmentation allows the use of small input samples (hundreds to thousands of cells) by first enriching the target proteins before analysis, thereby resolving the contradiction between identification accuracy and cell quantity requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method performs preliminary enrichment of the protein complex through Co-immunoprecipitation before the actual protein identification step. By pre-concentrating the target proteins and removing background interference, the subsequent RPPA analysis can achieve high sensitivity and accuracy with minimal input material, thus solving the problem of requiring millions of cells for traditional mass spectrometry approaches.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If conventional Co-IP followed by traditional analysis methods is used, then protein complexes are isolated, but the process is labor-intensive and not conducive to high-throughput analysis

Engineering Contradiction:
Improveprotein complex isolationVSAvoidanalysis throughput
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The method replaces traditional mechanical and manual analysis procedures with automated RPPA technology. The RPPA system uses robotic liquid handling, automated array printing, and high-throughput imaging/detection systems to analyze protein complexes. This substitution transforms the labor-intensive Co-IP process into a high-throughput workflow capable of simultaneously analyzing hundreds of samples, thereby resolving the contradiction between ease of complex isolation and analysis productivity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If traditional PPI exploration methods are used, then protein interactions are identified, but sample purification is labor-intensive and time-consuming

Engineering Contradiction:
ImprovePPI identificationVSAvoidsample purification time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The RPPA detection system serves multiple functions simultaneously: it detects and quantifies multiple proteins within the isolated complex, determines their activation states through phosphorylation-specific antibodies, and provides kinetic information about protein interactions. This multi-functionality allows comprehensive PPI analysis to be achieved in a single high-throughput assay, eliminating the need for multiple separate purification and analysis steps, thereby resolving the contradiction between identification precision and time consumption.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables the capture of hundreds of protein interactions simultaneously with high sensitivity and from minimal cell numbers, providing qualitative, quantitative, and kinetic read-outs of PPI, suitable for exploring disease mechanisms and identifying therapeutic targets.

Implementation Method 1

performing a protein complex immunoprecipitation (Co-IP) on the sample

Methodology Applied
Scientific EffectAntigen-antibody interaction: Adsorption

Implementation Method 2

performing a reverse phase protein array (RPPA) on the sample after Co-IP

Methodology Applied
Scientific EffectAntibody binding: Adsorption

Data Source

PatentUS11408896B2Methods for discovering protein-protein interactions
Publication Date: 2022.08.09 GEORGE MASON UNIV OF FAIRFAX VIRGINIA

AI summary

An embodiment relates to a method, comprising: obtaining a biological sample, performing a protein complex immunoprecipitation (Co-IP) on the sample, performing a reverse phase protein array (RPPA) on the sample after performing the protein complex immunoprecipitation, and identifying one or more protein complexes. A further embodiment relates to a method of treatment, comprising: obtaining a tissue sample from a patient, performing Co-IP then RPPA on the sample, identifying a protein complex, determining whether the protein complex comprises known protein drug targets, and treating the patient with a drug that interacts with the known protein drug targets.