Wen-Chieh Liao, Kim Herman, Zhenfen Zhao, Steven Stoesz, and Roberto
Campos-Gonzalez
Sponsored by
R&D Systems, Inc.
Published in
September 2010
2010
(p.3)
DOI: 10.2144/000113522
Sponsored,vendor-submitted protocol
Quantification of intracellular proteins and phosphorylation events is
extremely important for biomedical research. Although Western blot is the
most widely used method, it is labor intensive and time-consuming,
especially when analyzing multiple samples. The plate-based immunoassay has
become a popular alternative method for rapid protein detection. We have
developed a fluorogenic Cell-Based ELISA that does not require lysate
preparation or the multiple subsequent steps required for Western blot
analysis. The Cell-Based ELISA format allows two target cellular proteins,
or events, to be analyzed simultaneously in the same well, thus minimizing
well-to-well variability.
Cells are grown in 96-well plates and treated with the appropriate conditions,
such as inhibitors or ligand stimulation. The cells are then fixed and
permeabilized in the wells. This is followed by incubation with two primary
antibodies derived from different species: a phospho-specific antibody and a
normalization antibody that recognizes the total protein regardless of its
phosphorylation status. Species-specific secondary antibodies labeled with
horseradish peroxidase (HRP) and alkaline phosphatase (AP), and spectrally
distinct fluorogenic substrates for each enzyme, are used for detection. The
fluorescence of the phosphorylated protein is normalized to that of the
total protein in each well to correct for well-to-well variations.
Cell-Based ELISAs have been used to evaluate the effects of stimulators and
inhibitors on cultured cells, and this has been accomplished with 10,000
cells, or less, per well. For example, phosphorylation of JNK (T183/Y185),
Akt (S473), EGF R (Y1068), FRS2 (Y436), total protein levels of IkB-a
induced by various stimuli, and the effects of kinase inhibitors, were
assessed here using the Cell- Based ELISA method. The results were compared
with Western blot and traditional sandwich ELISA. Once the cells are plated
on 96-well microplates, the total hands-on time for the Cell-Based ELISA is
approximately 3 hours, which is significantly less than other techniques. In
addition, Cell-Based ELISAs are amenable to high-throughput applications and
may prove a valuable addition to kinase inhibitor screening strategies.
More Information
Do you have question about this Poster? Would you like more information about this poster?
Submit your questions here and BioTechniques will forward your question and contact information from our
database to an expert at
R&D Systems, Inc.