Anti-sigma factors
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Date: 2022-01-07

Anti-sigma factors, by Wikipedia https://en.wikipedia.org/wiki?curid=10016089 / CC BY SA 3.0

#Gene_expression
Cartoon representation of T4 anti-sigma factor Audrey Stevens' Inhibitor, PDB entry 1jr5 In the regulation of gene expression in prokaryotes, anti-sigma factors bind to sigma factors and inhibit transcriptional activity.
Anti-sigma factors have been found in a number of bacteria, including Escherichia coli and Salmonella, and in the T4 bacteriophage.
Anti-sigma factors are antagonists to the sigma factors, which regulate numerous cell processes including flagellar production, stress response, transport and cellular growth.
For example, anti-sigma factor 70 Rsd in E. coli is present in the stationary phase and blocks the activity of sigma factor 70 which in essence initiates gene transcription.
This allows the sigma S factor to associate with RNA polymerase and direct the expression of the stationary genes.
Although binding of Rsd to σ70 has been shown and numerous structural studies on Rsd have been performed, the detailed mechanism of action is still unknown.
Anti-sigma factor binds to sigma factor and inhibits its activity.
Sigma factor is an important protein which starts the transcription by binding with RNAP, anti-sigma factor is a protein which inhibits the activities
of sigma factor affect by several mechanism such as add up anti-sigma factor between sigma or twist the anti-sigma factor around sigma.
"In bacteria, the regulation of gene expression is the basis for adaptability, morphogenesis, and cellular differentiation. From all the different regulatory layers, regulation
of transcription initiation is a very important step for controlling gene expression." Each sigma factor has an associated anti-sigma factor which regulates it.
These anti-sigma factors are divided into either cytoplasmic or inner membrane bound anti-sigma factors.
Cytoplasmic bound anti-sigma factors are made up of FlgM, DnaK, RssB, & HscC. Inner membrane bound anti-sigma factors...