The actin cytoskeleton inhibits pore expansion during PIV5 fusion protein-promoted cell-cell fusion.
Paramyxovirus fusion (F) proteins promote both virus-cell fusion, required for viral entry, and cell-cell fusion, resulting in syncytia formation. We used the F-actin stabilizing drug, jasplakinolide, and the G-actin sequestrant, latrunculin A, to examine the role of actin dynamics in cell-cell fusion mediated by the parainfluenza virus 5 (PIV5) F protein. Jasplakinolide treatment caused a dose-dependent increase in cell-cell fusion as measured by both syncytia and reporter gene assays, and latrunculin A treatment also resulted in fusion stimulation. Treatment with jasplakinolide or latrunculin A partially rescued a fusion pore opening defect caused by deletion of the PIV5 F protein cytoplasmic tail, but these drugs had no effect on fusion inhibited at earlier stages by either temperature arrest or by a PIV5 heptad repeat peptide. These data suggest that the cortical actin cytoskeleton is an important regulator of fusion pore enlargement, an energetically costly stage of viral fusion protein-mediated membrane merger.
Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536-0509, USA.
Mark A
MA
Wurth
Rachel M
RM
Schowalter
Everett Clinton
EC
Smith
Carole L
CL
Moncman
Rebecca Ellis
RE
Dutch
Richard O
RO
McCann
D000199:Actins / Q000378:metabolism*; D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000378:metabolism; D002459:Cell Fusion; D002460:Cell Line; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003599:Cytoskeleton / Q000378:metabolism*; D047630:Depsipeptides / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D010252:Paramyxoviridae / Q000502:physiology*; D053778:Thiazolidines / Q000378:metabolism; D014760:Viral Fusion Proteins / Q000378:metabolism*
D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D047630:Depsipeptides; D053778:Thiazolidines; D014760:Viral Fusion Proteins; C057531:jasplakinolide; C037067:latrunculin A