Surface density of the Hendra G protein modulates Hendra F protein-promoted membrane fusion: role for Hendra G protein trafficking and degradation.
Hendra virus, like most paramyxoviruses, requires both a fusion (F) and attachment (G) protein for promotion of cell-cell fusion. Recent studies determined that Hendra F is proteolytically processed by the cellular protease cathepsin L after endocytosis. This unique cathepsin L processing results in a small percentage of Hendra F on the cell surface. To determine how the surface densities of the two Hendra glycoproteins affect fusion promotion, we performed experiments that varied the levels of glycoproteins expressed in transfected cells. Using two different fusion assays, we found a marked increase in fusion when expression of the Hendra G protein was increased, with a 1:1 molar ratio of Hendra F:G on the cell surface resulting in optimal membrane fusion. Our results also showed that Hendra G protein levels are modulated by both more rapid protein turnover and slower protein trafficking than is seen for Hendra F.
Whitman
Shannon D
SD
Department of Molecular and Cellular Biochemistry, University of Kentucky, College of Medicine, Biomedical Biological Sciences Research Building, 741 South Limestone, Lexington, KY 40536-0509, USA.
Dutch
Rebecca Ellis
RE
D000818:Animals; D000954:Antigens, Surface; D056668:Cathepsin L; D002403:Cathepsins / Q000378:metabolism; D002459:Cell Fusion; D002460:Cell Line; D003546:Cysteine Endopeptidases / Q000378:metabolism; D045404:Hendra Virus / Q000472:pathogenicity / Q000502:physiology*; D045464:Henipavirus Infections / Q000821:virology*; D006801:Humans; D008561:Membrane Fusion; D010447:Peptide Hydrolases / Q000378:metabolism; D021381:Protein Transport; D014759:Viral Envelope Proteins / Q000032:analysis / Q000378:metabolism*; D014760:Viral Fusion Proteins / Q000032:analysis / Q000378:metabolism*; D014779:Virus Replication
D000954:Antigens, Surface; D014759:Viral Envelope Proteins; D014760:Viral Fusion Proteins; C116204:attachment protein G; D002403:Cathepsins; D010447:Peptide Hydrolases; D003546:Cysteine Endopeptidases; C534281:CTSL protein, human; D056668:Cathepsin L