Transcription factors (TFs) are a group of cellular proteins that play essential roles in regulating gene expression. They act as sensors to monitor cellular change and convert the signals into gene expression. Often, TFs regulate gene expression not only through directly binding to their DNA binding site on the target promoter region, but also by interacting with other transcription factors or regulators. Since changes in transcriptional interaction patterns can have dramatic effects on gene expression and cellular responses to stimuli, monitoring multiple TF/TF and TF/co-regulator interactions simultaneously could obtain a better understanding of regulatory mechanisms. Signosis TF Protein Interaction Plate Array I can monitor TF/TF or TF/co-regulator interactions among 48 different TFs simultaneously in relation to one TF or co-regulator of interest.