Abstract
The PIV-5 hemagglutinin-neuraminidase (HN) protein is a multifunctional protein with sialic acid binding, neuraminidase and fusion promotion activity. HN is internalized by clathrin-mediated endocytosis and degraded. HN lacks internalization signals in its cytoplasmic tail but a single glutamic acid present at residue 37 at the putative transmembrane/ectodomain boundary is critical. We rescued rPIV-5 with mutations E37D or E37K, which have been shown to impair or abolish HN internalization, respectively. These viruses exhibited growth properties similar to wild-type (wt) virus but are impaired for fitness in tissue culture. Biochemical analysis of HN activities showed differences between HN E37D and HN E37K in fusion promotion and incorporation of HN and F into virions. Furthermore, oligomeric analyses indicate that HN E37 mutants perturb the tetrameric organization of HN, probably by destabilizing the dimer-of-dimers interface.
Original language | English (US) |
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Pages (from-to) | 189-201 |
Number of pages | 13 |
Journal | Virology |
Volume | 406 |
Issue number | 2 |
DOIs | |
State | Published - Oct 2010 |
Funding
We are grateful to David Waning and Anthony Schmitt who originally made the HN E37D and HN E37K constructs, respectively. We are grateful to George Leser for many discussions about HN internalization experiments. The Northwestern University Keck Biophysics Facility was used for the circular dichroism measurements and the facility is supported by a Cancer Center Support Grant ( NCI CA060553 ). This research was supported in part by a Public Health Services grant AI-23173 from the National Institute of Allergy and Infectious Diseases . J.G.R. was supported by predoctoral training grant T32 AI060523 from the National Institute of Allergy and Infectious Diseases . R.A.L. is an investigator of the Howard Hughes Medical Institute.
Keywords
- Degradation
- Hemagglutinin-neuraminidase protein
- Paramyxoviruses
- Protein oligomerization
- Reverse genetics
- Viral fitness
ASJC Scopus subject areas
- Virology