YscT

YscT is a protein encoded by the yscT gene in certain Gram-negative bacteria, most notably species of the genus Yersinia, including Yersinia pestis and Yersinia enterocolitica. It is part of the type III secretion system (T3SS), a syringe-like apparatus used to translocate effector proteins into host cells during infection.

Genetic and regulatory context: The yscT gene is typically part of the ysc operon on the virulence plasmid and is co-transcribed with other ysc genes. Expression of yscT is controlled by virulence regulators responsive to host-related cues, such as the LcrF/VirF regulatory circuit in Yersinia species.

Molecular role and phenotype: YscT is considered a component of the secretion system machinery, with predictions that it participates in assembly or stabilization of the basal apparatus. The precise localization and interactions vary, but it is generally associated with the inner membrane/periplasmic region of the T3SS. Experimental disruption of yscT often leads to reduced secretion of effector proteins and attenuated virulence in animal models.

Homology and nomenclature: YscT has homologs in other bacteria carrying type III secretion systems, where corresponding proteins are commonly designated SctT. The Ysc designation reflects its origin in Yersinia species, and the broader Sct nomenclature is used across bacterial genera.

See also: Type III secretion system, Yersinia, Ysc.