title: YscU recognizes translocators as export substrates of the Yersinia injectisome.
abstract: YscU is an essential component of the export apparatus of the Yersinia injectisome. It consists of an N-terminal transmembrane domain and a long cytoplasmic C-terminal domain, which undergoes auto-cleavage at a NPTH site. Substitutions N263A and P264A prevented cleavage of YscU and abolished export of LcrV, YopB and YopD but not of Yop effectors. As a consequence, yscU(N263A) mutant bacteria made needles without the LcrV tip complex and they could not form translocation pores. The graft of the export signal of the effector YopE, at the N-terminus of LcrV, restored LcrV export and assembly of the tip complex. Thus, YscU cleavage is required to acquire the conformation allowing recognition of translocators, which represent an individual category of substrates in the hierarchy of export. In addition, yscU(N263A) mutant bacteria exported reduced amounts of the YscP ruler and made longer needles. Increasing YscP export resulted in needles with normal size, depending on the length of the ruler. Hence, the effect of the yscU(N263A) mutation on needle length was the consequence of a reduced YscP export.
authors.affiliation: Infection Biology, Biozentrum der Universität Basel, Klingelbergstrasse 50-70, CH 4056 Basel, Switzerland.
authors.forename: Isabel
authors.initials: I
authors.lastname: Sorg
authors.forename: Stefanie
authors.initials: S
authors.lastname: Wagner
authors.forename: Marlise
authors.initials: M
authors.lastname: Amstutz
authors.forename: Shirley A
authors.initials: SA
authors.lastname: Müller
authors.forename: Petr
authors.initials: P
authors.lastname: Broz
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Lussi
authors.forename: Andreas
authors.initials: A
authors.lastname: Engel
authors.forename: Guy R
authors.initials: GR
authors.lastname: Cornelis
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D009154:Mutation; D011485:Protein Binding; D021381:Protein Transport; D015007:Yersinia / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D001426:Bacterial Proteins