scholarly journals Infectious Bronchitis Virus E Protein Is Targeted to the Golgi Complex and Directs Release of Virus-Like Particles

2000 ◽  
Vol 74 (9) ◽  
pp. 4319-4326 ◽  
Author(s):  
Emily Corse ◽  
Carolyn E. Machamer
Keyword(s):  
Golgi Complex ◽  
Infectious Bronchitis Virus ◽  
Virus Assembly ◽  
Recombinant Vaccinia Virus ◽  
Biological Properties ◽  
Infectious Bronchitis ◽  
E Protein ◽  
N Terminus ◽  
Low Levels ◽  
In Cells

ABSTRACT The coronavirus E protein is a poorly characterized small envelope protein present in low levels in virions. We are interested in the role of E in the intracellular targeting of infectious bronchitis virus (IBV) membrane proteins. We generated a cDNA clone of IBV E and antibodies to the E protein to study its cell biological properties in the absence of virus infection. We show that IBV E is an integral membrane protein when expressed in cells from cDNA. Epitope-specific antibodies revealed that the C terminus of IBV E is cytoplasmic and the N terminus is translocated. The short luminal N terminus of IBV E contains a consensus site for N-linked glycosylation, but the site is not used. When expressed using recombinant vaccinia virus, the IBV E protein is released from cells at low levels in sedimentable particles that have a density similar to that of coronavirus virions. The IBV M protein is incorporated into these particles when present. Indirect immunofluorescence microscopy showed that E is localized to the Golgi complex in cells transiently expressing IBV E. When coexpressed with IBV M, both from cDNA and in IBV infection, the two proteins are colocalized in Golgi membranes, near the coronavirus budding site. Thus, even though IBV E is present at low levels in virions, it is apparently expressed at high levels in infected cells near the site of virus assembly.

scholarly journals The Cytoplasmic Tail of Infectious Bronchitis Virus E Protein Directs Golgi Targeting

2002 ◽  
Vol 76 (3) ◽  
pp. 1273-1284 ◽  
Author(s):  
Emily Corse ◽  
Carolyn E. Machamer
Keyword(s):  
Golgi Complex ◽  
Infectious Bronchitis Virus ◽  
Transmembrane Domain ◽  
Brefeldin A ◽  
Cytoplasmic Tail ◽  
Reporter Protein ◽  
Infectious Bronchitis ◽  
E Protein ◽  
Necessary And Sufficient ◽  
Golgi Matrix

ABSTRACT We have previously shown that the E protein of the coronavirus infectious bronchitis virus (IBV) is localized to the Golgi complex when expressed exogenously from cDNA. Here, we report that neither the transmembrane domain nor the short lumenal domain of IBV E is required for Golgi targeting. However, an N-terminal truncation containing only the cytoplasmic domain (CTE) was efficiently localized to the Golgi complex, and this domain could retain a reporter protein in the Golgi. Thus, the cytoplasmic tail of the E protein is necessary and sufficient for Golgi targeting. The IBV E protein is palmitoylated on one or two cysteine residues adjacent to its transmembrane domain, but palmitoylation was not required for proper Golgi targeting. Using C-terminal truncations, we determined that the IBV E Golgi targeting information is present between tail amino acids 13 and 63. Upon treatment with brefeldin A, both the E and CTE proteins redistributed to punctate structures that colocalized with the Golgi matrix proteins GM130 and p115 instead of being localized to the endoplasmic reticulum like Golgi glycosylation enzymes. This suggests that IBV E is associated with the Golgi matrix through interactions of its cytoplasmic tail and may have interesting implications for coronavirus assembly in early Golgi compartments.

scholarly journals The SARS CoV-1 3a protein disrupts Golgi complex morphology and cargo trafficking

2021 ◽  
Author(s):  
Rex R. Gonzales ◽  
Carolyn E. Machamer
Keyword(s):  
Infectious Bronchitis Virus ◽  
Viral Proteins ◽  
Transfected Cells ◽  
Infectious Bronchitis ◽  
E Protein ◽  
Complex Morphology ◽  
Universal Feature ◽  
Infected Cells ◽  
Intermediate Compartment ◽  
Acidic Compartments

Coronaviruses assemble by budding into the endoplasmic reticulum-Golgi intermediate compartment, but the pathway of egress from infected cells is not well understood. Efficient egress of infectious bronchitis virus (a gamma coronavirus, CoV) requires neutralization of Golgi pH by the envelope (E) protein. This results in reduced rates of cargo traffic and disrupts Golgi morphology, but it protects the spike protein from aberrant proteolysis. The severe acute respiratory syndrome (SARS) CoV-1 E protein does not disrupt the Golgi, however. We show here that in transfected cells, the ORF3a protein of SARS CoV-1 disrupts Golgi morphology, cargo trafficking and luminal pH. Unlike the infectious bronchitis virus E protein, these functions of the SARS CoV-1 3a protein appear to require its viroporin activity. Thus, neutralization of acidic compartments may be a universal feature of CoV infection, although different viral proteins and mechanisms may be used to achieve this outcome.

scholarly journals Elucidation of the avian nucleolar proteome by quantitative proteomics using SILAC and changes in cells infected with the coronavirus infectious bronchitis virus

PROTEOMICS ◽  
2010 ◽  
Vol 10 (19) ◽  
pp. 3558-3562 ◽  
Author(s):  
Edward Emmott ◽  
Catriona Smith ◽  
Stevan R. Emmett ◽  
Brian K. Dove ◽  
Julian A. Hiscox
Keyword(s):  
Infectious Bronchitis Virus ◽  
Quantitative Proteomics ◽  
Infectious Bronchitis ◽  
In Cells
Sign in / Sign up

Export Citation Format

Share Document