YscP, a Yersinia protein required for Yop secretion that is surface exposed, and released in low Ca 2
The Yersinia Ysc apparatus is made of more than 20 proteins, 11 of which have homologues in many type III systems. Here, we characterize YscP from Yersinia enterocolitica . This 515‐residue protein has a high proline content, a large tandem repetition and a slow migration in SDS–PAGE. Unlike the pro...
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Published in | Molecular microbiology Vol. 37; no. 5; pp. 1005 - 1018 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
01.09.2000
|
Online Access | Get full text |
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Summary: | The
Yersinia
Ysc apparatus is made of more than 20 proteins, 11 of which have homologues in many type III systems. Here, we characterize YscP from
Yersinia enterocolitica
. This 515‐residue protein has a high proline content, a large tandem repetition and a slow migration in SDS–PAGE. Unlike the products of neighbouring genes, it has a counterpart only in
Pseudomonas aeruginosa
and it varies even between
Yersinia
Ysc machineries. An
yscP
Δ97−465
mutant was unable to secrete any Yop, even under conditions overcoming feedback inhibition of Yop synthesis. Interestingly, a cloned
yscP
Δ57−324
from
Yersinia pestis
introduced in the
yscP
Δ97−465
mutant can sustain a significant Yop secretion and thus partially complemented the mutation. This explains the leaky phenotype observed with the
yscP
mutant of
Y. pestis
. In accordance with this secretion deficiency, YscP is required for the delivery of Yop effectors into macrophages. Mechanical shearing, immunolabelling and electron microscopy experiments showed that YscP is exposed at the bacterial surface when bacteria are incubated at 37°C in the presence of Ca
2+
and thus do not secrete Yops. At 37°C, when Ca
2+
ions are chelated, YscP is released like a Yop protein. We conclude that YscP is a part of the Ysc injectisome which is localized at the bacterial surface and is destabilized by Ca
2+
chelation. |
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ISSN: | 0950-382X 1365-2958 |
DOI: | 10.1046/j.1365-2958.2000.02026.x |