Interactome Mapping: Using Protein Microarray Technology to Reconstruct Diverse Protein Networks

Uzoma, Ijeoma; Zhu, Heng

While protein microarrays leverage the advantage of uniform protein expression, for proteomics, their impact is limited by the extent of coverage. A remarkable advance was put forth by the Zhu laboratory with the construction of the first human proteome microarray containing over 17,000 full length pro-teins [16] , the largest available to date (Figure 3) . The discovery potential for this technology is dramatically increased by expanded proteome coverage. Multiple large-scale studies intended to link PTM substrates with their upstream enzymes, such as kinases, SUMO E3 ligases and ubiquitin ligases, are ongoing with the human proteome microarrays. As the number of bona fide PTMs increase and more substrates are found to acquire numerous modifications, we cannot ignore coregulation of PTMs. Directed studies to recapitulate crosstalk between enzymes, PTMs and their common substrates are possible with protein microarrays and may uncover key nodes of regulation and critical points where pathways converge. While MS is an ideal technology for the discovery of novel PTMs, such as the crotonylation PTM [69] , it is not well suited to identify the enzymes responsible for novel modification. The richness of 17,000 natively-purified proteins on a single surface provides an ideal platform for discovery of novel enzyme function. The human proteome array can also be harnessed as a tool for high-throughput characterization of monoclonal antibody (mAb) specificity from hybridomas [16] .