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SipB-SipC complex is essential for translocon formation
Sebenzile K Myeni1, Lu Wang, Daoguo Zhou
1Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America.
Plos One
|April 2, 2013
Summary
Salmonella uses translocator proteins SipC and SipB to deliver effector proteins into host cells. SipC requires SipB interaction for membrane insertion, forming a translocon channel.
Area of Science:
- Microbiology
- Molecular Biology
- Cell Biology
Background:
- Salmonella employs a type III secretion system (TTSS) to inject effector proteins into host cells.
- Translocator proteins, such as SipC and SipB, are crucial for breaching the host cell membrane.
- The precise mechanism of translocator insertion into host membranes is not fully understood.
Purpose of the Study:
- To elucidate the molecular mechanism of SipC and SipB insertion into host cell membranes.
- To identify the role of SipC-SipB complex formation in translocator function.
Main Methods:
- Investigated SipC C-terminal mutants for their ability to interact with SipB.
- Assessed membrane insertion of SipC and its mutants using cell fractionation techniques.
- Analyzed the requirement of SipB for SipC membrane localization.
Main Results:
- The C-terminal region of SipC (amino acids 340-409) is essential for interacting with SipB.
- SipC insertion into the host membrane is dependent on its interaction with SipB.
- SipC mutants unable to bind SipB failed to insert into the host cell membrane.
- SipC was not found in the membrane fraction in the absence of SipB.
Conclusions:
- SipC-SipB complex formation is critical for translocator insertion into host membranes.
- A proposed mechanism involves SipC binding SipB via its C-terminus to facilitate membrane insertion and translocon assembly.
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