The cowpox virus fusion regulator proteins SPI-3 and hemagglutinin interact in infected and uninfected cells

Journal Article · Thu Mar 30 04:00:00 EST 2006 · Virology

DOI:https://doi.org/10.1016/J.VIROL.2005.1· OSTI ID:20779474

Turner, Peter C ^[1]; Moyer, Richard W ^[1]

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1. Department of Molecular Genetics and Microbiology, Box 100266/1600 SW Archer Road, ARB R2-231, University of Florida, Gainesville, FL 32610-0266 (United States)

The serpin SPI-3 and the hemagglutinin (HA) encoded by cowpox virus (CPV) block cell-cell fusion, and colocalize at the cell surface. wtCPV does not fuse cells, but inactivation of either gene leads to fusion. SPI-3 mAb added to wtCPV-infected cells caused fusion, confirming that SPI-3 protein at the cell surface prevents fusion. The SPI-3 mAb epitope mapped to an 85-amino acid region at the C-terminus. Removal of either 44 residues from the SPI-3 C-terminus or 48 residues following the N-terminal signal sequence resulted in fusion. Interaction between SPI-3 and HA proteins in infected cells was shown by coimmunoprecipitation. SPI-3/HA was not associated with the A27L 'fusion' protein. SPI-3 and HA were able to associate in uninfected cells in the absence of other viral proteins. The HA-binding domain in SPI-3 resided in the C-terminal 229 residues, and did not include helix D, which mediates cofactor interaction in many other serpins.

• OSTI ID: 20779474
• Journal Information: Virology, Journal Name: Virology Journal Issue: 1 Vol. 347; ISSN VIRLAX; ISSN 0042-6822
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
AMINO ACIDS
GENES
INACTIVATION
PROTEINS
VIRUSES