Actin assembly in response to extracellular signals: role of capping proteins, thymosin beta 4 and profilin

Semin Cell Biol. 1994 Jun;5(3):183-91. doi: 10.1006/scel.1994.1023.


In motile non-muscle cells, G-actin sequestering proteins, capping proteins and profilin regulate actin assembly in response to extracellular signals. The regulation of actin sequestration/assembly is performed via the control of the concentration of free G-actin at steady-state. The increase in free G-actin mediated by capping proteins results in an increased sequestration of actin. When barbed ends are uncapped upon cell stimulation, the participation of profilin-actin in filament assembly causes a decrease in free G-actin, which results in the depletion of the pool of sequestered actin and concomitant increase in the F-actin pool.

Publication types

  • Review

MeSH terms

  • Actin Depolymerizing Factors
  • Actins / physiology*
  • Adenosine Triphosphate / metabolism
  • Animals
  • Contractile Proteins / physiology
  • Destrin
  • Microfilament Proteins / physiology*
  • Profilins
  • Signal Transduction / physiology*
  • Thymosin / physiology*


  • Actin Depolymerizing Factors
  • Actins
  • Contractile Proteins
  • Destrin
  • Microfilament Proteins
  • Profilins
  • thymosin beta(4)
  • Thymosin
  • Adenosine Triphosphate