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Evidence for an interaction between the membrane protein of a paramyxovirus and actin
Abstract:
Evidence for an interaction of the membrane (M) protein of Newcastle disease and Sendai viruses with cellular actin was obtained by three different techniques. M protein linked to Sepharose 4B was found to bind actin, but not myoglobin or bovine serum albumin, and to selectively remove actin from a mixture of these three proteins. Sedimentation of a mixture of M protein and F-actin through a sucrose gradient resulted in sedimentation of M protein with actin. Control proteins, bovine serum albumin and cytochrome c, did not sediment with actin. In circular dichroism studies, M protein added to actin in a 1:1 complex resulted in a significant increase in negative ellipticity at 220 nm, which corresponds to an increase in alpha-helix and a decrease in beta-structure and random coil. This is indicative of an interaction between M protein and actin. It is possible that the frequent identification of cellular actin in a number of enveloped viruses may be attributed to the interaction of actin and M protein or its equivalent.
Insights
Newcastle disease virus and Sendai virus membrane (M) proteins interact with cellular actin. This interaction, confirmed by multiple methods, may explain actin
Area of Science:
- Virology
- Molecular Biology
- Biochemistry
Background:
- Cellular actin is frequently identified in enveloped viruses.
- The role of viral proteins in this association is not fully understood.
Purpose of the Study:
- To investigate the interaction between the membrane (M) protein of Newcastle disease virus and Sendai virus with cellular actin.
Main Methods:
- Affinity chromatography using M protein linked to Sepharose 4B.
- Sucrose gradient sedimentation assays.
- Circular dichroism spectroscopy.
Main Results:
- M protein selectively bound and co-sedimented with actin, but not control proteins.
- Circular dichroism indicated M protein binding induces conformational changes in actin, increasing alpha-helix content.
Conclusions:
- Evidence supports a direct interaction between viral M protein and cellular actin.
- This interaction may contribute to the presence of actin in enveloped viruses.