📄 A single tyrosine in the severe acute respiratory syndrome coronavirus membrane protein cytoplasmic tail is important for efficient interaction with spike protein

Severe acute respiratory syndrome coronavirus (SARS-CoV) encodes 3 major envelope proteins: spike (S), membrane (M), and envelope (E). Previous work identified a dibasic endoplasmic reticulum retrieval signal in the cytoplasmic tail of SARS-CoV S that promotes efficient interaction with SARS-CoV M. The dibasic signal was shown to be important for concentrating S near the virus assembly site rather than for direct interaction with M. Here, we investigated the sequence requirements of the SARS-CoV M protein that are necessary for interaction with SARS-CoV S. The SARS-CoV M tail was shown to be necessary for S localization in the Golgi region when the proteins were exogenously coexpressed in cells. This was specific, since SARS-CoV M did not retain an unrelated glycoprotein in the Golgi. Importantly, we found that an essential tyrosine residue in the SARS-CoV M cytoplasmic tail, Y195, was important for S-M interaction. When Y195 was mutated to alanine, MY195A no longer retained S intracellularly at the Golgi. Unlike wild-type M, M Y195A did not reduce the amount of SARS-CoV S carbohydrate processing or surface levels when the two proteins were coexpressed. Mutating Y 195 also disrupted SARS-CoV S-M interaction in vitro. These results suggest that Y195 is necessary for efficient SARS-CoV S-M interaction and, thus, has a significant involvement in assembly of infectious virus. Copyright © 2010, American Society for Microbiology.

keywords 🔗 syndrome coronavirus (1074) 🔗 endoplasmic reticulum (78) 🔗 infectious virus (88) 🔗 respiratory syndrome (2004) 🔗 results suggest (206) 🔗 acute respiratory (1734)

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