Arp2/3 complex

Atomic structure of bovine Arp2/3 complex (PDB code: 1k8k).[1] Color coding for subunits: Arp3, orange; Arp2, marine (subunits 1 & 2 not resolved and thus not shown); p40, green; p34, ice blue; p20, dark blue; p21, magenta; p16, yellow.

Arp2/3 complex (Actin Related Protein 2/3 complex) is a seven-subunit protein complex that plays a major role in the regulation of the actin cytoskeleton. It is a major component of the actin cytoskeleton and is found in most actin cytoskeleton-containing eukaryotic cells.[2] Two of its subunits, the Actin-Related Proteins ARP2 and ARP3, closely resemble the structure of monomeric actin and serve as nucleation sites for new actin filaments. The complex binds to the sides of existing ("mother") filaments and initiates growth of a new ("daughter") filament at a distinctive 70-degree angle from the mother. Branched actin networks are created as a result of this nucleation of new filaments. The regulation of rearrangements of the actin cytoskeleton is important for processes like cell locomotion, phagocytosis, and intracellular motility of lipid vesicles.

The Arp2/3 complex was named after it was identified in 1994 by affinity chromatography from Acanthamoeba castellanii,[3] though it had been previously isolated in 1989 in a search for proteins that bind to actin filaments in Drosophila melanogaster embryos.[4] It is found in most eukaryotic organisms, but absent from a number of Chromalveolates and plants.[2]

  1. ^ Cite error: The named reference Robinson_2001 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Veltman_2010 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Machesky_1994 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Miller_1989 was invoked but never defined (see the help page).