Exploring the roles of diaphanous and enabled activity in shaping the balance between filopodia and lamellipodia.

Abstract

During migration cell protrusions power cell extension and sample the environment. Different cells produce different protrusions, from keratocytes dominated by lamellipodia, to growth cones combining filopodia and lamellipodia, to dendritic spines. One key challenge is to determine how the toolkit of actin regulators are coordinated to generate these diverse protrusive arrays. Here we use Drosophila leading-edge (LE) cells to explore how Diaphanous (Dia)-related formins and Ena/VASP proteins cooperate in this process. We first dissect the Dia regulatory region, revealing novel roles for the GTPase-binding and FH3 domains in cortical localization, filopodial initiation, and lengthening. Second, we provide evidence that activating Dia mobilizes Ena from storage places near the LE to act at the LE. Further, Dia and Ena coIP and can recruit one another to new locations, suggesting cooperation is key to their mechanisms of action. Third, we directly explore the functional relationship between Dia and Ena, varying their levels and activity separately in the same cell type. Surprisingly, although each is sufficient to induce filopodia, together they induce lamellipodia. Our data suggest they work together in a complex and nonadditive way, with the ratio between active Dia and Ena being one factor that modulates the balance between filopodia and lamellipodia.

• Authors: Catarina C F Homem, Mark Peifer
• Journal: Molecular biology of the cell (Mol Biol Cell) Vol. 20 Issue 24 Pg. 5138-55 (Dec 2009) ISSN: 1939-4586 [Electronic] United States
• PMID: 19846663 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Actins
• Carrier Proteins
• Cell Adhesion Molecules
• Drosophila Proteins
• Formins
• Microfilament Proteins
• Phosphoproteins
• diaphanous protein, Drosophila
• vasodilator-stimulated phosphoprotein
• rho GTP-Binding Proteins

Topics

• Actins (metabolism)
• Animals
• Carrier Proteins (chemistry, metabolism)
• Cell Adhesion Molecules (metabolism)
• Cytoplasm (metabolism)
• Drosophila Proteins (chemistry, metabolism)
• Drosophila melanogaster (embryology, enzymology, growth & development, metabolism)
• Enzyme Activation
• Formins
• Genes, Dominant
• Immunoprecipitation
• Microfilament Proteins (metabolism)
• Morphogenesis
• Phenotype
• Phosphoproteins (metabolism)
• Protein Structure, Tertiary
• Protein Transport
• Pseudopodia (metabolism)
• Sequence Deletion
• rho GTP-Binding Proteins (metabolism)