How profilin promotes actin filament assembly in the presence of thymosin β4
1993; Cell Press; Volume: 75; Issue: 5 Linguagem: Inglês
10.1016/0092-8674(93)90544-z
ISSN1097-4172
AutoresDominique Pantaloni, Marie‐France Carlier,
Tópico(s)Advanced Fluorescence Microscopy Techniques
ResumoThe role of profilin in the regulation of actin assembly has been reexamined. The affinity of profilin for ATP-actin appears 10-fold higher than previously thought. In the presence of ATP, the participation of the profilin-actin complex to filament elongation at the barbed end is linked to a decrease in the steady-state concentration of globular actin. This surprising effect is made possible by the involvement of the irreversible ATP hydrolysis accompanying actin polymerization. As a consequence, in the presence of thymosin beta 4 (T beta 4), low amounts of profilin promote extensive actin assembly off of the pool of actin-T beta 4 complex. When barbed ends are capped, profilin simply sequesters globular actin. A model is proposed for the function of profilin in actin-based motility.
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