Gene expression as a multilevel reaction cascade. Schematic of the complex reaction cascade of gene expression. Deregulation of TF levels or activity can putatively occur along any step in the pathway, from synthesis steps such as transcription (µ_{Transcription}) and translation (µ_Translation), to degradation steps such as the decay of mRNA (δ_mrna) and protein (δ_protein), to dynamic processes such as posttranslational modifications by ligand activated pathways (K_PTM), to shuttling dynamics (K_Shuttle), and finally to target locus search and binding (K_TF-Target).