PMID:10438834

Citation	de Haan, CA, Smeets, M, Vernooij, F, Vennema, H and Rottier, PJ (1999) Mapping of the coronavirus membrane protein domains involved in interaction with the spike protein. J. Virol. 73:7441-52
Abstract	The coronavirus membrane (M) protein is the key player in virion assembly. One of its functions is to mediate the incorporation of the spikes into the viral envelope. Heterotypic interactions between M and the spike (S) protein can be demonstrated by coimmunoprecipitation and by immunofluorescence colocalization, after coexpression of their genes in eukaryotic cells. Using these assays in a mutagenetic approach, we have mapped the domains in the M protein that are involved in complex formation between M and S. It appeared that the 25-residue luminally exposed amino-terminal domain of the M protein is not important for M-S interaction. A 15-residue deletion, the insertion of a His tag, and replacement of the ectodomain by that of another coronavirus M protein did not affect the ability of the M protein to associate with the S protein. However, complex formation was sensitive to changes in the transmembrane domains of this triple-spanning protein. Deletion of either the first two or the last two transmembrane domains, known not to affect the topology of the protein, led to a considerable decrease in complex formation, but association was not completely abrogated. Various effects of changes in the part of the M protein that is located at the cytoplasmic face of the membrane were observed. Deletions of the extreme carboxy-terminal tail appeared not to interfere with M-S complex formation. However, deletions in the amphipathic domain severely affected M-S interaction. Interestingly, changes in the amino-terminal and extreme carboxy-terminal domains of M, which did not disrupt the interaction with S, are known to be fatal to the ability of the protein to engage in virus particle formation (C. A. M. de Haan, L. Kuo, P. S. Masters, H. Vennema, and P. J. M. Rottier, J. Virol. 72:6838-6850, 1998). Apparently, the structural requirements of the M protein for virus particle assembly differ from the requirements for the formation of M-S complexes.
Links	PubMed PMC104271
Keywords	Animals; Binding Sites; Cats; Cell Line; Cell Membrane/metabolism; Chromosome Mapping; Cricetinae; Membrane Glycoproteins/genetics; Membrane Glycoproteins/metabolism; Murine hepatitis virus/genetics; Murine hepatitis virus/metabolism; Mutagenesis; Precipitin Tests; Spike Glycoprotein, Coronavirus; Viral Envelope Proteins/genetics; Viral Envelope Proteins/metabolism; Viral Matrix Proteins/genetics; Viral Matrix Proteins/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
CVMA5:VME1	part_of	GO:0044177: host cell Golgi apparatus	ECO:0000314: direct assay evidence used in manual assertion		C		Seeded From UniProt	complete
CVMA5:VME1		GO:0044177: host cell Golgi apparatus	ECO:0000314:		C		Figure 7. "The M protein was found to accumulate in the Golgi complex, as documented previously. This localization did not change when the S protein was coexpressed (see Fig. 7B)"	complete CACAO 10501
CVMA5:SPIKE		GO:0044177: host cell Golgi apparatus	ECO:0000314:		C		Figure 7. "the S protein coaccumulated with M in the Golgi complex, although a faint reticular staining pattern was still detectable (see Fig. 7C)"	complete CACAO 10502
CVMA5:SPIKE	Colocalizes with	GO:0044165: host cell endoplasmic reticulum	ECO:0000314:		C		Figure 7. "a faint reticular staining pattern was still detectable (see Fig. 7C)" "As shown in Fig. 7, the reticular ER-like staining pattern of S [...]"	complete CACAO 10504
CVMA5:SPIKE	part_of	GO:0044177: host cell Golgi apparatus	ECO:0000314: direct assay evidence used in manual assertion		C		Seeded From UniProt	complete
CVMA5:SPIKE	colocalizes_with	GO:0044165: host cell endoplasmic reticulum	ECO:0000314: direct assay evidence used in manual assertion		C		Seeded From UniProt	complete

References

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