High throughput assay systems and methods for identifying agents that alter expression of cellular proteins

A method of identifying an agent that alters the level of surface expression of a membrane ion channel in a mammalian cell, said method comprising:

• a) preparing a medium containing mammalian cells that express said membrane ion channel;
• b) adding to said medium containing mammalian cells a test amount of a candidate agent;
• c) incubating said cells in the presence of said candidate agent for at least 16 hours;
• d) treating said cells with an amount of a fixative effective to stabilize said cells for subsequent processing and examination;
• e) adding to said medium containing mammalian cells, candidate agent and fixative of step (d) at least one antibody which binds to at least one extracellular epitope of said membrane ion channel in an amount effective to measurably bind to said membrane ion channel wherein said extracellular epitope contains a tag;
• and
• f) detecting the level of binding of said antibody to said at least one extracellular epitope of said membrane ion channel with said candidate agent, wherein a change in said level of binding relative to control indicates that said candidate agent alters the level of surface expression of said membrane ion channel, wherein said control comprises said medium containing mammalian cells that express said membrane ion channel in an amount equal to that in step (a) and said at least one antibody in an amount equal to that added in step (e).