Isoform diversity in the Arp2/3 complex determines actin filament dynamics

Nat Cell Biol. 2016 Jan;18(1):76-86. doi: 10.1038/ncb3286. Epub 2015 Dec 14.


The Arp2/3 complex consists of seven evolutionarily conserved subunits (Arp2, Arp3 and ARPC1-5) and plays an essential role in generating branched actin filament networks during many different cellular processes. In mammals, however, the ARPC1 and ARPC5 subunits are each encoded by two isoforms that are 67% identical. This raises the possibility that Arp2/3 complexes with different properties may exist. We found that Arp2/3 complexes containing ARPC1B and ARPC5L are significantly better at promoting actin assembly than those with ARPC1A and ARPC5, both in cells and in vitro. Branched actin networks induced by complexes containing ARPC1B or ARPC5L are also disassembled ∼2-fold slower than those formed by their counterparts. This difference reflects the ability of cortactin to stabilize ARPC1B- and ARPC5L- but not ARPC1A- and ARPC5-containing complexes against coronin-mediated disassembly. Our observations demonstrate that the Arp2/3 complex in higher eukaryotes is actually a family of complexes with different properties.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Actin-Related Protein 2 / metabolism*
  • Actin-Related Protein 3 / metabolism*
  • Angiopoietin-like Proteins
  • Angiopoietins / metabolism*
  • Animals
  • Cell Line
  • Cortactin / metabolism
  • Humans
  • Mice
  • Microfilament Proteins / metabolism*
  • Protein Isoforms / chemistry
  • Protein Isoforms / metabolism


  • ACTR2 protein, human
  • ACTR3 protein, human
  • Actin-Related Protein 2
  • Actin-Related Protein 3
  • Actr3 protein, mouse
  • Angiopoietin-like Proteins
  • Angiopoietins
  • Angptl2 protein, mouse
  • CTTN protein, human
  • Cortactin
  • Cttn protein, mouse
  • Microfilament Proteins
  • Protein Isoforms
  • coronin proteins