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Regulatory mechanisms required for DE-cadherin function in cell migration and other types of adhesion.

Pacquelet A, Rørth P - J. Cell Biol. (2005)

Bottom Line: We have investigated the requirements for Drosophila melanogaster epithelial (DE) cadherin regulation in vivo.We found that (1) although linking DE-cadherin to alpha-catenin is essential, regulation of the link is not required in any of these types of adhesion; (2) beta-catenin is required only to link DE-cadherin to alpha-catenin; and (3) the cytoplasmic domain of DE-cadherin has an additional specific function for the invasive migration of border cells, which is conserved to other cadherins.The nature of this additional function is discussed.

View Article: PubMed Central - PubMed

Affiliation: European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany.

ABSTRACT
Cadherin-mediated adhesion can be regulated at many levels, as demonstrated by detailed analysis in cell lines. We have investigated the requirements for Drosophila melanogaster epithelial (DE) cadherin regulation in vivo. Investigating D. melanogaster oogenesis as a model system allowed the dissection of DE-cadherin function in several types of adhesion: cell sorting, cell positioning, epithelial integrity, and the cadherin-dependent process of border cell migration. We generated multiple fusions between DE-cadherin and alpha-catenin as well as point-mutated beta-catenin and analyzed their ability to support these types of adhesion. We found that (1) although linking DE-cadherin to alpha-catenin is essential, regulation of the link is not required in any of these types of adhesion; (2) beta-catenin is required only to link DE-cadherin to alpha-catenin; and (3) the cytoplasmic domain of DE-cadherin has an additional specific function for the invasive migration of border cells, which is conserved to other cadherins. The nature of this additional function is discussed.

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Analysis of β-catenin–Y667F function. (A) Schematic representation of β-catenin. Sequences flanking Y654 in mouse β-catenin and the corresponding Y667 in D. melanogaster β-catenin (arm) are indicated. (B–I) arm mutant clones sort away from wild-type cells and display epithelial integrity defects. (C and F) Stage 6 egg chambers; arrows indicate resulting discontinuity in the epithelium. Compare with wild-type clones in B and E. β-catenin–Y667F rescues both sorting (D and H) and follicular epithelium integrity (D, G, and I) even at late stages of oogenesis (H and I, stage 10 egg chambers). Phalloidin (red) stains F-actin, and mutant clones are indicated by an absence of GFP (green) or by the green line (below the line in D and H and between the lines in G and I). (J–L) Oocyte positioning and border cell migration in arm mutant clones expressing the indicated β-catenin transgenes. In nurse cell clones (J and L), β-catenin–wt and β-catenin–Y667F were expressed from an arm promoter. In follicle and border cell clones (D, G–I, and K), they were expressed as UAS transgenes with the MARCM system. Bars (B–G), 30 μm; (H and I) 20 μm.
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fig2: Analysis of β-catenin–Y667F function. (A) Schematic representation of β-catenin. Sequences flanking Y654 in mouse β-catenin and the corresponding Y667 in D. melanogaster β-catenin (arm) are indicated. (B–I) arm mutant clones sort away from wild-type cells and display epithelial integrity defects. (C and F) Stage 6 egg chambers; arrows indicate resulting discontinuity in the epithelium. Compare with wild-type clones in B and E. β-catenin–Y667F rescues both sorting (D and H) and follicular epithelium integrity (D, G, and I) even at late stages of oogenesis (H and I, stage 10 egg chambers). Phalloidin (red) stains F-actin, and mutant clones are indicated by an absence of GFP (green) or by the green line (below the line in D and H and between the lines in G and I). (J–L) Oocyte positioning and border cell migration in arm mutant clones expressing the indicated β-catenin transgenes. In nurse cell clones (J and L), β-catenin–wt and β-catenin–Y667F were expressed from an arm promoter. In follicle and border cell clones (D, G–I, and K), they were expressed as UAS transgenes with the MARCM system. Bars (B–G), 30 μm; (H and I) 20 μm.

Mentions: Mutations in armadillo (arm), which is the single D. melanogaster β-catenin gene, give rise to phenotypes that show its requirement in cadherin-dependent adhesion. During oogenesis, arm- mutant germ line clones cause oocyte mispositioning (Fig. 2 J; Peifer et al., 1993; Godt and Tepass, 1998; González-Reyes and St. Johnston, 1998). Also, in the follicular epithelium, arm mutant cells sort away from wild-type cells and lose their epithelial integrity (Fig. 2, C and F; González-Reyes and St. Johnston, 1998; Tanentzapf et al., 2000). arm- mutant follicle cells lose their epithelial integrity earlier than shg mutant cells, which is likely a result of the presence of both Drosophila neural (DN) and DE-cadherin in early follicle cells (Tanentzapf et al., 2000). Also, arm mutant border cells do not migrate (Fig. 2 K). In nurse cells, lack of β-catenin strongly inhibits migration without completely blocking it (Fig. 2 L; Peifer et al., 1993). The linkage to the cytoskeleton via β-catenin may be less critical for cadherin to function as substratum than in the actively migrating cell itself. Finally, a mutant form of DE-cadherin that is unable to bind β-catenin is also not able to mediate adhesion during D. melanogaster oogenesis (Pacquelet et al., 2003), confirming that interaction with β-catenin is essential for DE-cadherin function.


Regulatory mechanisms required for DE-cadherin function in cell migration and other types of adhesion.

Pacquelet A, Rørth P - J. Cell Biol. (2005)

Analysis of β-catenin–Y667F function. (A) Schematic representation of β-catenin. Sequences flanking Y654 in mouse β-catenin and the corresponding Y667 in D. melanogaster β-catenin (arm) are indicated. (B–I) arm mutant clones sort away from wild-type cells and display epithelial integrity defects. (C and F) Stage 6 egg chambers; arrows indicate resulting discontinuity in the epithelium. Compare with wild-type clones in B and E. β-catenin–Y667F rescues both sorting (D and H) and follicular epithelium integrity (D, G, and I) even at late stages of oogenesis (H and I, stage 10 egg chambers). Phalloidin (red) stains F-actin, and mutant clones are indicated by an absence of GFP (green) or by the green line (below the line in D and H and between the lines in G and I). (J–L) Oocyte positioning and border cell migration in arm mutant clones expressing the indicated β-catenin transgenes. In nurse cell clones (J and L), β-catenin–wt and β-catenin–Y667F were expressed from an arm promoter. In follicle and border cell clones (D, G–I, and K), they were expressed as UAS transgenes with the MARCM system. Bars (B–G), 30 μm; (H and I) 20 μm.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2171345&req=5

fig2: Analysis of β-catenin–Y667F function. (A) Schematic representation of β-catenin. Sequences flanking Y654 in mouse β-catenin and the corresponding Y667 in D. melanogaster β-catenin (arm) are indicated. (B–I) arm mutant clones sort away from wild-type cells and display epithelial integrity defects. (C and F) Stage 6 egg chambers; arrows indicate resulting discontinuity in the epithelium. Compare with wild-type clones in B and E. β-catenin–Y667F rescues both sorting (D and H) and follicular epithelium integrity (D, G, and I) even at late stages of oogenesis (H and I, stage 10 egg chambers). Phalloidin (red) stains F-actin, and mutant clones are indicated by an absence of GFP (green) or by the green line (below the line in D and H and between the lines in G and I). (J–L) Oocyte positioning and border cell migration in arm mutant clones expressing the indicated β-catenin transgenes. In nurse cell clones (J and L), β-catenin–wt and β-catenin–Y667F were expressed from an arm promoter. In follicle and border cell clones (D, G–I, and K), they were expressed as UAS transgenes with the MARCM system. Bars (B–G), 30 μm; (H and I) 20 μm.
Mentions: Mutations in armadillo (arm), which is the single D. melanogaster β-catenin gene, give rise to phenotypes that show its requirement in cadherin-dependent adhesion. During oogenesis, arm- mutant germ line clones cause oocyte mispositioning (Fig. 2 J; Peifer et al., 1993; Godt and Tepass, 1998; González-Reyes and St. Johnston, 1998). Also, in the follicular epithelium, arm mutant cells sort away from wild-type cells and lose their epithelial integrity (Fig. 2, C and F; González-Reyes and St. Johnston, 1998; Tanentzapf et al., 2000). arm- mutant follicle cells lose their epithelial integrity earlier than shg mutant cells, which is likely a result of the presence of both Drosophila neural (DN) and DE-cadherin in early follicle cells (Tanentzapf et al., 2000). Also, arm mutant border cells do not migrate (Fig. 2 K). In nurse cells, lack of β-catenin strongly inhibits migration without completely blocking it (Fig. 2 L; Peifer et al., 1993). The linkage to the cytoskeleton via β-catenin may be less critical for cadherin to function as substratum than in the actively migrating cell itself. Finally, a mutant form of DE-cadherin that is unable to bind β-catenin is also not able to mediate adhesion during D. melanogaster oogenesis (Pacquelet et al., 2003), confirming that interaction with β-catenin is essential for DE-cadherin function.

Bottom Line: We have investigated the requirements for Drosophila melanogaster epithelial (DE) cadherin regulation in vivo.We found that (1) although linking DE-cadherin to alpha-catenin is essential, regulation of the link is not required in any of these types of adhesion; (2) beta-catenin is required only to link DE-cadherin to alpha-catenin; and (3) the cytoplasmic domain of DE-cadherin has an additional specific function for the invasive migration of border cells, which is conserved to other cadherins.The nature of this additional function is discussed.

View Article: PubMed Central - PubMed

Affiliation: European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany.

ABSTRACT
Cadherin-mediated adhesion can be regulated at many levels, as demonstrated by detailed analysis in cell lines. We have investigated the requirements for Drosophila melanogaster epithelial (DE) cadherin regulation in vivo. Investigating D. melanogaster oogenesis as a model system allowed the dissection of DE-cadherin function in several types of adhesion: cell sorting, cell positioning, epithelial integrity, and the cadherin-dependent process of border cell migration. We generated multiple fusions between DE-cadherin and alpha-catenin as well as point-mutated beta-catenin and analyzed their ability to support these types of adhesion. We found that (1) although linking DE-cadherin to alpha-catenin is essential, regulation of the link is not required in any of these types of adhesion; (2) beta-catenin is required only to link DE-cadherin to alpha-catenin; and (3) the cytoplasmic domain of DE-cadherin has an additional specific function for the invasive migration of border cells, which is conserved to other cadherins. The nature of this additional function is discussed.

Show MeSH
Related in: MedlinePlus