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Host cell-dependent lateral mobility of viral glycoproteins
S L Lydy1, S Basak, R W Compans
1Department of Microbiology, University of Alabama, Birmingham 35294.
Abstract:
The lateral mobility of viral envelope proteins on the plasma membranes of infected cells is an important factor in both virus assembly and pathogenesis. The envelope glycoproteins of measles and human parainfluenza virus are mobile on the surfaces of infected HeLa cells and undergo lateral redistribution in the presence of specific antibody, forming unipolar caps. In contrast, no such redistribution was observed with influenza virus hemagglutinin (HA) or vesicular stomatitis virus (VSV) G glycoproteins on infected HeLa cell surfaces. However, the HA and G glycoproteins were both found to be mobile in the plasma membrane of CV-1 cells, or human or murine peritoneal macrophages. These results indicate that host cell-dependent as well as virus-specific factors are involved in determining viral glycoprotein mobility. No significant differences in the patterns of synthesis of influenza or VSV viral proteins were found in the various cell types examined. The HA and G proteins, when expressed from vaccinia virus recombinants, were each found to be immobile in HeLa cells and mobile in CV-1 cells, thus indicating that the host cell-dependent differences in mobility are an intrinsic property of each viral glycoprotein molecule and not the result of interaction with other viral components. It is suggested that the association of viral glycoproteins with either the cytoskeleton or membrane-associated cellular proteins may be related to the observed differences in lateral mobility.
Insights
Viral glycoproteins exhibit cell-dependent mobility, influencing virus assembly and pathogenesis. Mobility differences are intrinsic to viral proteins, not viral interactions, suggesting cytoskeleton involvement.
Area of Science:
- Virology
- Cell Biology
- Immunology
Background:
- Viral envelope protein mobility on host cell membranes is crucial for virus assembly and pathogenesis.
- Measles and human parainfluenza virus glycoproteins redistribute with antibodies, unlike influenza HA and VSV G proteins on HeLa cells.
Purpose of the Study:
- To investigate the factors influencing viral envelope glycoprotein lateral mobility on infected host cell surfaces.
- To determine if host cell type or virus-specific factors dictate glycoprotein mobility.
Main Methods:
- Comparing mobility of measles, human parainfluenza virus, influenza hemagglutinin (HA), and vesicular stomatitis virus (VSV) G glycoproteins on HeLa cells, CV-1 cells, macrophages, and using vaccinia virus recombinants.
- Analyzing viral protein synthesis patterns across different cell types.
Main Results:
- Influenza HA and VSV G glycoproteins were mobile on CV-1 cells and macrophages but immobile on HeLa cells.
- Measles and human parainfluenza virus glycoproteins showed mobility and redistribution on HeLa cells.
- When expressed via vaccinia virus, HA and G proteins were immobile in HeLa cells but mobile in CV-1 cells.
Conclusions:
- Viral glycoprotein mobility is influenced by host cell-dependent factors, not solely by virus-specific elements.
- Differences in mobility are intrinsic properties of the viral glycoproteins themselves.
- Association with the host cell cytoskeleton or membrane proteins may explain observed mobility variations.