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ERp29 triggers a conformational change in polyomavirus to stimulate membrane binding
Brian Magnuson1, Emily K Rainey, Thomas Benjamin
1Department of Cell and Developmental Biology, University of Michigan Medical School, 4643 Medical Sciences II, 1335 East Catherine Street, Ann Arbor, Michigan 48109, USA.
Molecular Cell
|October 26, 2005
Summary
The endoplasmic reticulum protein ERp29 facilitates polyomavirus (Py) infection by exposing viral proteins, enabling membrane penetration. This suggests PDI family proteins generally aid viral entry and ER remodeling.
Area of Science:
- Virology
- Cell Biology
- Protein Chemistry
Background:
- Membrane penetration by nonenveloped viruses is a critical but poorly understood step in viral infection.
- The endoplasmic reticulum (ER) lumen is a key site for viral conformational changes preceding cytosolic entry.
Purpose of the Study:
- To investigate the early stages of nonenveloped virus membrane penetration.
- To identify host factors within the ER that mediate viral entry.
Main Methods:
- Studying conformational changes of polyomavirus (Py) within the ER lumen.
- Assessing the role of ERp29 using dominant-negative expression.
- Comparing viral entry mechanisms with that of cholera toxin.
Main Results:
- ERp29 exposes the C-terminal arm of Py's VP1 protein, promoting hydrophobic interactions with lipid bilayers.
- ERp29 facilitates polyomavirus infection, as evidenced by decreased infection rates with dominant-negative ERp29.
- Cholera toxin, another ER-translocated agent, is unfolded by PDI family proteins.
Conclusions:
- ERp29 is an ER factor that mediates membrane penetration for nonenveloped viruses like polyomavirus.
- PDI family proteins likely play a general role in ER remodeling events, including viral entry.