Microwestern Arrays for Systems-Level Analysis of SH2 Domain-Containing Proteins.

The Microwestern Array (MWA) method combines the scalability and miniaturization afforded by the Reverse Phase Lysate Array (RPLA) approach with the electrophoretic separation characteristic of the Western blot. This technology emulates the creation of an array of small Western blots on a single sheet of nitrocellulose allowing for the sensitive and quantitative measurement of hundreds of proteins from hundreds of cell lysates with minimal cost and maximal accuracy, precision, and reproducibility. The MWA is a versatile technology that can be easily configured for purposes such as antibody screening, cell signaling network inference, protein modification/phenotype regression analysis, and genomic/proteomic relationships. Accordingly, configurations for the MWA can be optimized for maximal numbers of proteins analyzed from small numbers of cell lysates, for small numbers of antibodies against large numbers of cell lysates, or for maximal resolution of protein size achieved by increased electrophoretic separation distance. For example, on a single gel, 6 samples can be printed 96 times if a few samples need to be assayed with a large number of antibodies. Alternatively, up to 100 samples can be assayed with four antibodies on a single gel. Intermediate configurations are also discussed.The efficiency of the MWA is orders of magnitude greater in reagents, labor, and time required per data point relative to the standard Western blotting method and orders of magnitude more sensitive than standard mass spectrometry methods. The MWA is therefore a very attractive approach for capturing global changes in protein abundances and modifications including tyrosine phosphorylation and SH2 domain binding sites.