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Divergent roles of β‐ and γ‐actin isoforms during spread of vaccinia virus
Author(s) -
Marzook N. Bishara,
Latham Sharissa L.,
Lynn Helena,
Mckenzie Christopher,
Chaponnier Christine,
Grau Georges E.,
Newsome Timothy P.
Publication year - 2017
Publication title -
cytoskeleton
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 86
eISSN - 1949-3592
pISSN - 1949-3584
DOI - 10.1002/cm.21356
Subject(s) - biology , actin , microbiology and biotechnology , actin remodeling of neurons , gene isoform , actin remodeling , virus , mdia1 , cytoplasm , colocalization , vaccinia , actin cytoskeleton , cytoskeleton , virology , cell , biochemistry , gene , recombinant dna
Actin is a major component of the cytoskeleton and is present as two isoforms in non‐muscle cells: β‐ and γ‐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 β‐ and γ‐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 β‐actin. Knockdown of β‐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.