Role of N-Linked Glycosylation of the 5-HT2A Receptor in JC Virus Infection

Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship Street, Providence, RI 02903, USA.
Journal of Virology (Impact Factor: 4.44). 10/2010; 84(19):9677-84. DOI: 10.1128/JVI.00978-10
Source: PubMed


JC virus (JCV) is a human polyomavirus and the causative agent of the fatal demyelinating disease progressive multifocal leukoencephalopathy
(PML). JCV infection of host cells is dependent on interactions with cell surface asparagine (N)-linked sialic acids and the
serotonin 5-hydroxytryptamine2A receptor (5-HT2AR). The 5-HT2AR contains five potential N-linked glycosylation sites on the extracellular N terminus. Glycosylation of other serotonin receptors
is essential for expression, ligand binding, and receptor function. Also, glycosylation of cellular receptors has been reported
to be important for JCV infection. Therefore, we hypothesized that the 5-HT2AR N-linked glycosylation sites are required for JCV infection. Treatment of 5-HT2AR-expressing cells with tunicamycin, an inhibitor of N-linked glycosylation, reduced JCV infection. Individual mutation of
each of the five N-linked glycosylation sites did not affect the capacity of 5-HT2AR to support JCV infection and did not alter the cell surface expression of the receptor. However, mutation of all five N-linked
glycosylation sites simultaneously reduced the capacity of 5-HT2AR to support infection and altered the cell surface expression. Similarly, tunicamycin treatment reduced the cell surface
expression of 5-HT2AR. Mutation of all five N-linked glycosylation sites or tunicamycin treatment of cells expressing wild-type 5-HT2AR resulted in an altered electrophoretic mobility profile of the receptor. Treatment of cells with PNGase F, to remove N-linked
oligosaccharides from the cell surface, did not affect JCV infection in 5-HT2AR-expressing cells. These data affirm the importance of 5-HT2AR as a JCV receptor and demonstrate that the sialic acid component of the receptor is not directly linked to 5-HT2AR.

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