Regulation by Alternative Sigma Factors

摘要: This chapter summarizes the alternative sigma factors of two model organisms (Escherichia coli and Bacillus subtilis), describes types regulatory pathways that have evolved to control σ activity, presents a glimpse at some recently discovered variations on these already established themes. In addition, many stress-induced proteins were initially identified using proteomics named for inducing stress(es). Examples include general stress (GSP) heat shock (HSP). Regulation σS proteolysis plays major role in controlling activation this response by starvation diverse nutrients several other stresses. Although full implications complex architecture are not yet clear, number advantages apparent. First, branched pathway allows integration distinct classes signals and, within each signaling pathway, there likely multiple targets thereby enabling further diversity inputs. Second, use reversible protein modifications (phosphorylation/ dephosphorylation) enables rapid changing conditions also system be rapidly shut off once homeostatic restored. Third, regulate activity may ultimately more energy efficient than those systems rely instead destruction an anti-σ with consequent need new synthesis reset system. Sporulation B. subtilis was first process unambiguously shown s its execution thus holds special place historical development factor biology.