Proteasome inhibition assay and methods of use

A method of determining an effect of a proteasome activity on a target cell comprising:

• a) contacting a biological sample comprising one or more target cells with a proteasome effector;
• b) contacting the biological sample treated with the proteasome effector with an IκB degradation agonist to activate the one or more target cells in the biological sample;
• c) contacting the activated biological sample with a first labeled binding agent that is capable of binding IκB;
• d) detecting a target in the biological sample of c);
• e) determining an amount of the first labeled binding agent bound to the detected target cell, thereby detecting an amount of proteasome activity in the target cell in the presence of the proteasome effector;
• and
• f) comparing the amount of proteasome activity of the target cell in the presence of the proteasome effector to a target cell in the absence of the proteasome effector, thereby determining an effect of the proteasome effector on the proteasome activity in the target cell.

A method of identifying a proteasome effector comprising:

• a) contacting a biological sample comprising one or more target cells with a candidate proteasome effector;
• b) contacting the biological sample treated with the candidate proteasome effector with an IκB degradation agonist to activate the one or more target cells in the biological sample;
• c) contacting the activated biological sample with a first labeled binding agent that is capable of binding IκB;
• d) detecting a target cell in the biological sample of c);
• e) detecting an amount of the first labeled binding agent bound to the detected target cell;
• and
• f) comparing the amount of the first labeled binding agent bound to the detected target cell to a control sample, wherein a difference in the amount of the first labeled binding agent bound to the detected target cell compared to the control sample indicates the composition is a proteasome effector.