Related Experiment Video

Updated: Aug 15, 2026

Visualization and Quantitative Analysis of Genotoxin-Induced PARP1/PARP2 Activation in Cells Using a Fluorescent Fusion Protein-Based Reporter
07:53

Visualization and Quantitative Analysis of Genotoxin-Induced PARP1/PARP2 Activation in Cells Using a Fluorescent Fusion Protein-Based Reporter

Published on: April 17, 2026

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
PubMed

Insights

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.

More Related Videos

Conformational Evaluation of HIV-1 Trimeric Envelope Glycoproteins Using a Cell-based ELISA Assay07:10

Conformational Evaluation of HIV-1 Trimeric Envelope Glycoproteins Using a Cell-based ELISA Assay

Published on: September 14, 2014

Monitoring Activation of the Antiviral Pattern Recognition Receptors RIG-I And PKR By Limited Protease Digestion and Native PAGE12:43

Monitoring Activation of the Antiviral Pattern Recognition Receptors RIG-I And PKR By Limited Protease Digestion and Native PAGE

Published on: July 29, 2014

Related Concept Videos

Rab Proteins01:14

Rab Proteins

Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Inhibitors Of Virion Release01:25

Inhibitors Of Virion Release

Viral replication and dissemination rely on efficient mechanisms for host cell entry, genome replication, assembly, and release. Influenza viruses, such as types A and B, are negative-sense single-stranded RNA viruses with a segmented genome, that depend on two critical surface glycoproteins to carry out these processes: hemagglutinin (HA) and neuraminidase (NA). HA initiates infection by binding to sialic acid residues on the surface of host epithelial cells, facilitating receptor-mediated...
Inhibitors of Virion Maturation and Assembly01:19

Inhibitors of Virion Maturation and Assembly

As part of their replication cycle, certain viruses synthesize long precursor proteins called polyproteins within infected host cells. In human immunodeficiency virus (HIV), two major polyproteins are produced: Gag and Gag-Pol. The Gag polyprotein supplies the structural components of the virus, while Gag-Pol includes essential viral enzymes such as reverse transcriptase, integrase, and protease. After synthesis, these polyproteins move to the host cell membrane, where they assemble into an...
Leaky Scanning02:28

Leaky Scanning

During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA.  Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
Coat Assembly and GTPases01:33

Coat Assembly and GTPases

Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Retrovirus Life Cycles01:10

Retrovirus Life Cycles

Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the retrovirus to...