Abstract:
:Type IV secretion systems are virulence determinants in many bacteria and share extensive homology with many conjugal transfer systems. Although type IV systems and their homologues have been studied widely, the mechanism by which substrates are secreted remains unclear. In Agrobacterium, we show that type IV secretion substrates that lack signal peptides form a soluble complex in the periplasm with the virulence protein VirJ. Additionally, these proteins co-precipitate with constituents of the type IV transporter: the VirB pilus and the VirD4 protein. Our findings suggest that the substrate proteins localized to the periplasm may associate with the pilus in a manner that is mediated by VirJ, and suggest a two-step process for type IV secretion in Agrobacterium. Our analyses of protein-protein interactions in a variety of mutant backgrounds indicate that substrates are probably secreted independently of one another.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Pantoja M,Chen L,Chen Y,Nester EWdoi
10.1046/j.1365-2958.2002.03098.xsubject
Has Abstractpub_date
2002-09-01 00:00:00pages
1325-35issue
5eissn
0950-382Xissn
1365-2958pii
3098journal_volume
45pub_type
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