Profilin induces lamellipodia by growth factor-independent mechanism
| Autor: | Enrique Syriani, Marta Bosch, Arcadi Gual, Xavier Gasull, Alicia Moya, Elena Abad, Azucena Gomez-Cabrero, Miguel Morales |
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| Rok vydání: | 2008 |
| Předmět: |
rac1 GTP-Binding Protein
Phalloidine Recombinant Fusion Proteins RAC1 macromolecular substances Biology Naphthalenes Biochemistry Phosphatidylinositol 3-Kinases Profilins Trabecular Meshwork Depsipeptides Genetics Animals Humans Pseudopodia Molecular Biology Actin Cells Cultured Actin remodeling Azepines Actin cytoskeleton Actins Cell biology Rats Profilin biology.protein Intercellular Signaling Peptides and Proteins Cattle MDia1 Lamellipodium Peptides Proto-Oncogene Proteins c-akt Biotechnology Binding domain |
| Zdroj: | FASEB journal : official publication of the Federation of American Societies for Experimental Biology. 22(5) |
| ISSN: | 1530-6860 |
| Popis: | Profilin has been implicated in cell motility and in a variety of cellular processes, such as membrane extension, endocytosis, and formation of focal complexes. In vivo, profilin replenish the pool of ATP-actin monomers by increasing the rate of nucleotide exchange of ADP-actin for ATP-actin, promoting the incorporation of new actin monomers at the barbed end of actin filaments. For this report, we generated a membrane-permeable version of profilin I (PTD4-PfnI) for the alteration of intracellular profilin levels taking advantage of the protein transduction technique. We show that profilin I induces lamellipodia formation independently of growth factor presence in primary bovine trabecular meshwork (BTM) cells. The effects are time- and concentration-dependent and specific to the profilin I isoform. Profilin II, the neuronal isoform, failed to extend lamellipodia in the same degree as profilin I. H133S, a mutation in the polyproline binding domain, showed a reduced ability to induce lamellipodia. H199E, mutation in the actin binding domain failed to induce membrane spreading and inhibit fetal bovine serum (FBS) -induced lamellipodia extension. Incubation with a synthetic polyproline domain peptide (GP5)3, fused to a transduction domain, abolished lamellipodia induction by profilin or FBS. Time-lapse microscopy confirmed the effects of profilin on lamellipodia extension with a higher spreading velocity than FBS. PTD4-Pfn I was found in the inner lamellipodia domain, at the membrane leading edge where it colocalizes with endogenous profilin. While FBS-induced lamellipodia formation activates Rac1, PTD4-Pfn I stimulation did not induce Rac1 activation. We propose a role of profilin I favoring lamellipodia formation by a mechanism downstream of growth factor. |
| Databáze: | OpenAIRE |
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