SctU
SctU is a conserved component of bacterial type III secretion systems (T3SS), a needle-like machinery used by many Gram-negative pathogens to inject proteins into host cells. It is an inner-membrane protein that forms part of the T3SS export apparatus, linking the cytoplasmic complex to the membrane-embedded secretion channel. SctU is found across various bacteria, with well-known orthologs such as YscU in Yersinia and SpaS in Salmonella.
Structurally, SctU is associated with the inner membrane and is involved in the assembly of the secretion
Functionally, SctU acts as a gatekeeper that regulates the order of substrate secretion by the T3SS. During
Mutations that disrupt SctU processing or function often impair T3SS activity, leading to defects in substrate