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Effects of profilin and profilactin on actin structure and function in living cells
- Source :
- The Journal of Cell Biology
- Publication Year :
- 1992
- Publisher :
- Rockefeller University Press, 1992.
-
Abstract
- Previous studies have yielded conflicting results concerning the physiological role of profilin, a 12-15-kD actin- and phosphoinositide-binding protein, as a regulator of actin polymerization. We have addressed this question by directly microinjecting mammalian profilins, prepared either from an E. coli expression system or from bovine brain, into living normal rat kidney (NRK) cells. The microinjection causes a dose-dependent decrease in F-actin content, as indicated by staining with fluorescent phalloidin, and a dramatic reduction of actin and alpha-actinin along stress fibers. In addition, it has a strong inhibitory effect toward the extension of lamellipodia. However, the injection of profilin causes no detectable perturbation to the cell-substrate focal contact and no apparent depolymerization of filaments in either the nonlamellipodial circumferential band or the contractile ring of dividing cells. Furthermore, cytokinesis of injected cells occurs normally as in control cells. In contrast to pure profilin, high-affinity profilin-actin complexes from brain induce an increase in total cellular F-actin content and an enhanced ruffling activity, suggesting that the complex may dissociate readily in the cell and that there may be multiple states of profilin that differ in their ability to bind or release actin molecules. Our results indicate that profilin and profilactin can function as effective regulators for at least a subset of actin filaments in living cells.
- Subjects :
- Phalloidin
Arp2/3 complex
macromolecular substances
Microfilament
Profilins
chemistry.chemical_compound
Actin remodeling of neurons
Contractile Proteins
Cell Movement
Animals
Actin-binding protein
Cells, Cultured
Dose-Response Relationship, Drug
biology
Microfilament Proteins
Proteins
Actin remodeling
Articles
Cell Biology
Actins
Rats
Cell biology
Microscopy, Fluorescence
chemistry
Profilin
biology.protein
MDia1
Subjects
Details
- ISSN :
- 15408140 and 00219525
- Volume :
- 117
- Database :
- OpenAIRE
- Journal :
- Journal of Cell Biology
- Accession number :
- edsair.doi.dedup.....b5fadb2ccbe36f398cccef8bc58718b5