The ubiquitin-proteasome system degrades regulatory proteins and thereby controls a broad range of cellular processes such as the cell cycle, DNA-repair, gene transcription and signal transduction. The proteasome typically degrades its substrates completely into small peptides. However, biological exceptions do occur. For example, the activity of a handful of transcriptional...
RNA interference (RNAi) is a newly discovered gene control pathway that silences gene expression in response to double-stranded RNA. This sequence-specific downregulation occurs at the level of mRNA stability, and is directed by the double-stranded RNA trigger itself. RNAi can be separated into two distinct steps; during the initiation phase,...