Premium
YscU cleavage and the assembly of Yersinia type III secretion machine complexes
Author(s) -
Riordan Kelly E.,
Schneewind Olaf
Publication year - 2008
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2008.06247.x
Subject(s) - secretion , biology , effector , cleavage (geology) , asparagine , mutant , microbiology and biotechnology , biochemistry , gene , enzyme , paleontology , fracture (geology)
Summary YscU, a component of the Yersinia type III secretion machine, promotes auto‐cleavage at asparagine 263 (N263). Mutants with an alanine substitution at yscU codon 263 displayed secretion defects for some substrates (LcrV, YopB and YopD); however, transport of effector proteins into host cells (YopE, YopH, YopM) continued to occur. Two yscU mutations were isolated that, unlike N263A , completely abolished type III secretion; YscU G127D promoted auto‐cleavage at N263, whereas YscU G270N did not. When fused to glutathione S‐transferase (Gst), the YscU C‐terminal cytoplasmic domain promoted auto‐cleavage and Gst‐YscU C also exerted a dominant‐negative phenotype by blocking type III secretion. Gst–YscU C/N263A caused a similar blockade and Gst–YscU C/G270N reduced secretion. Gst–YscU C and Gst–YscU C/N263A bound YscL, the regulator of the ATPase YscN, whereas Gst–YscU C/G270N did not. When isolated from Yersinia , Gst–YscU C and Gst–YscU C/N263A associated with YscK–YscL–YscQ; however, Gst–YscU C/G270N interacted predominantly with the machine component YscO, but not with YscK–YscL–YscQ. A model is proposed whereby YscU auto‐cleavage promotes interaction with YscL and recruitment of ATPase complexes that initiate type III secretion.