**6.4. Functional biomarkers as drug targets**

A decade ago, Labaer and colleagues evaluated functional properties of the proteins IVTT expressed onto the array by performing protein-protein interactions in high-throughput format. In this report, they printed an array expressing 647 unique genes in duplicate and tested for several well characterized interacting pairs including Jun-Fos and p53-MDM2 [33].

A more recent study, Manzano et al. published a work where they applied NAPPA to study protein interactions. In this study, a novel interactor partners were identified for P-selectin and phospholipase A2 and further validated [34].

Recently, a novel functional array, designed by Pascal Braun, identified novel cell signaling pathways in *Arabidopsis thaliana* by evaluating protein interactions onto this NAPPA technology [35].

In addition, a further study has just been published where evaluated multi-protein complex- in NAPPA format. In this study, four novel tuberculosis-related antigens where identified in- guinea pigs vaccinated with Bacillus Calmette-Guerin (BCG) and also validated with ELISA [36].
