TY - JOUR
T1 - Flexibility of the head-stalk linker domain of paramyxovirus HN glycoprotein is essential for triggering virus fusion
AU - Adu-Gyamfi, Emmanuel
AU - Kim, Lori S.
AU - Jardetzky, Theodore S.
AU - Lamb, Robert A.
N1 - Funding Information:
ACKNOWLEDGMENTS We thank George P. Leser for assistance with microscopy. This research was supported in part by National Institutes of Health Research Grants R01 AI 23173 (to R.A.L.) and R01 GM 61050 (to T.S.J.). R.A.L. is an Investigator of the Howard Hughes Medical Institute. E.A.-G. was supported by an UNCF-Merck Postdoctoral Science Research Fellowship.
Publisher Copyright:
© 2016, American Society for Microbiology.
PY - 2016
Y1 - 2016
N2 - The Paramyxoviridae comprise a large family of enveloped, negative-sense, single-stranded RNA viruses with significant economic and public health implications. For nearly all paramyxoviruses, infection is initiated by fusion of the viral and host cell plasma membranes in a pH-independent fashion. Fusion is orchestrated by the receptor binding protein hemagglutinin-neuraminidase (HN; also called H or G depending on the virus type) protein and a fusion (F) protein, the latter undergoing a major refolding process to merge the two membranes. Mechanistic details regarding the coupling of receptor binding to F activation are not fully understood. Here, we have identified the flexible loop region connecting the bulky enzymatically active head and the four-helix bundle stalk to be essential for fusion promotion. Proline substitution in this region of HN of parainfluenza virus 5 (PIV5) and Newcastle disease virus HN abolishes cell-cell fusion, whereas HN retains receptor binding and neuraminidase activity. By using reverse genetics, we engineered recombinant PIV5-EGFP viruses with mutations in the head-stalk linker region of HN. Mutations in this region abolished virus recovery and infectivity. In sum, our data suggest that the loop region acts as a "hinge" around which the bulky head of HN swings to-and-fro to facilitate timely HN-mediate F-triggering, a notion consistent with the stalk-mediated activation model of paramyxovirus fusion.
AB - The Paramyxoviridae comprise a large family of enveloped, negative-sense, single-stranded RNA viruses with significant economic and public health implications. For nearly all paramyxoviruses, infection is initiated by fusion of the viral and host cell plasma membranes in a pH-independent fashion. Fusion is orchestrated by the receptor binding protein hemagglutinin-neuraminidase (HN; also called H or G depending on the virus type) protein and a fusion (F) protein, the latter undergoing a major refolding process to merge the two membranes. Mechanistic details regarding the coupling of receptor binding to F activation are not fully understood. Here, we have identified the flexible loop region connecting the bulky enzymatically active head and the four-helix bundle stalk to be essential for fusion promotion. Proline substitution in this region of HN of parainfluenza virus 5 (PIV5) and Newcastle disease virus HN abolishes cell-cell fusion, whereas HN retains receptor binding and neuraminidase activity. By using reverse genetics, we engineered recombinant PIV5-EGFP viruses with mutations in the head-stalk linker region of HN. Mutations in this region abolished virus recovery and infectivity. In sum, our data suggest that the loop region acts as a "hinge" around which the bulky head of HN swings to-and-fro to facilitate timely HN-mediate F-triggering, a notion consistent with the stalk-mediated activation model of paramyxovirus fusion.
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U2 - 10.1128/JVI.01187-16
DO - 10.1128/JVI.01187-16
M3 - Article
C2 - 27489276
AN - SCOPUS:84990050127
SN - 0022-538X
VL - 90
SP - 9172
EP - 9181
JO - Journal of virology
JF - Journal of virology
IS - 20
ER -