Divergent roles of ?- and ?-actin isoforms during spread of vaccinia virus.

ABSTRACT: Actin is a major component of the cytoskeleton and is present as two isoforms in non-muscle cells: ?- and ?-cytoplasmic actin. These isoforms are strikingly conserved, differing by only four N-terminal amino acids. During spread from infected cells, vaccinia virus (VACV) particles induce localized actin nucleation that propel virus to surrounding cells and facilitate cell-to-cell spread of infection. Here we show that virus-tipped actin comets are composed of ?- and ?-actin. We employed isoform-specific siRNA knockdown to examine the role of the two isoforms in VACV-induced actin comets. Despite the high level of similarity between the actin isoforms, and their colocalization, VACV-induced actin nucleation was dependent exclusively on ?-actin. Knockdown of ?-actin led to a reduction in the release of virus from infected cells, a phenotype dependent on virus-induced Arp2/3 complex activity. We suggest that local concentrations of actin isoforms may regulate the activity of cellular actin nucleator complexes.

SUBMITTER: Marzook NB 

PROVIDER: S-EPMC7162416 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature