The WH2 Domain and Actin Nucleation: Necessary but Insufficient

Trends Biochem Sci. 2016 Jun;41(6):478-490. doi: 10.1016/j.tibs.2016.03.004. Epub 2016 Apr 5.

Abstract

Two types of sequences, proline-rich domains (PRDs) and the WASP-homology 2 (WH2) domain, are found in most actin filament nucleation and elongation factors discovered thus far. PRDs serve as a platform for protein-protein interactions, often mediating the binding of profilin-actin. The WH2 domain is an abundant actin monomer-binding motif comprising ∼17 amino acids. It frequently occurs in tandem repeats, and functions in nucleation by recruiting actin subunits to form the polymerization nucleus. It is found in Spire, Cordon Bleu (Cobl), Leiomodin (Lmod), Arp2/3 complex activators (WASP, WHAMM, WAVE, etc.), the bacterial nucleators VopL/VopF and Sca2, and some formins. Yet, it is argued here that the WH2 domain plays only an auxiliary role in nucleation, always synergizing with other domains or proteins for this activity.

Publication types

  • Review

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Actin Cytoskeleton / ultrastructure
  • Actin-Related Protein 2-3 Complex / metabolism*
  • Actin-Related Protein 2-3 Complex / ultrastructure
  • Actins / chemistry
  • Actins / genetics
  • Actins / metabolism
  • Amino Acid Sequence
  • Animals
  • Autoantigens / chemistry*
  • Autoantigens / genetics
  • Autoantigens / metabolism
  • Bacteria / genetics
  • Bacteria / metabolism
  • Cell Nucleus / genetics
  • Cell Nucleus / metabolism
  • Cytoskeletal Proteins / chemistry*
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / metabolism
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / metabolism
  • Fetal Proteins / chemistry*
  • Fetal Proteins / genetics
  • Fetal Proteins / metabolism
  • Formins
  • Humans
  • Microfilament Proteins / chemistry*
  • Microfilament Proteins / genetics
  • Microfilament Proteins / metabolism
  • Nuclear Proteins / chemistry*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Polymerization
  • Protein Interaction Domains and Motifs
  • Protein Structure, Secondary
  • Sequence Alignment
  • Sequence Homology, Amino Acid

Substances

  • Actin-Related Protein 2-3 Complex
  • Actins
  • Autoantigens
  • Cobl protein, human
  • Cytoskeletal Proteins
  • Fetal Proteins
  • Formins
  • LMOD1 protein, human
  • Microfilament Proteins
  • Nuclear Proteins
  • SPIRE1 protein, human