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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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Further analysis of DE-cadherinΔCyt/α-catenin phenotypes. (A) Migration defects of border cells expressing DE-cadherinΔCyt/α-catenin in shg mutant or wild-type background. (B) Migration defects of mixed border cell clusters. In each scored cluster, half of the border cells are wild type and half are as indicated (D–G). (C) DE-cadherin surface levels in wild-type cells expressing DE-cadherinΔCyt/α-catenin (below the green line). (D and E) Mixed border cell cluster, wild-type, and shg mutant cells. At stage 10, the full cluster has reached the oocyte (D), or shg mutant cells (E, arrow) are split from wild-type cells (E, arrowhead; incomplete migration in B). (F and G) Mixed border cell cluster, wild-type, and shg mutant cells expressing DE-cadherinΔCyt/α-catenin. At stage 10, the cluster has reached the oocyte (F) or is delayed (G, incomplete migration). (H–K) Centripetal cell migration and direct comparison of mutant (green) with wild-type cells. shg mutant cells (H, early; and I, late) show defects; shg mutant cells expressing DE-cadherinΔCyt/α-catenin (J, early; and K, late) show no defect (n = 23). Phalloidin (red) stains F-actin and DAPI (blue) stains nuclei. GFP (green) marks wild-type cells in D and E and mutant cells in F–K. Bars (C), 20 μm; (D–G) 80 μm.
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fig5: Further analysis of DE-cadherinΔCyt/α-catenin phenotypes. (A) Migration defects of border cells expressing DE-cadherinΔCyt/α-catenin in shg mutant or wild-type background. (B) Migration defects of mixed border cell clusters. In each scored cluster, half of the border cells are wild type and half are as indicated (D–G). (C) DE-cadherin surface levels in wild-type cells expressing DE-cadherinΔCyt/α-catenin (below the green line). (D and E) Mixed border cell cluster, wild-type, and shg mutant cells. At stage 10, the full cluster has reached the oocyte (D), or shg mutant cells (E, arrow) are split from wild-type cells (E, arrowhead; incomplete migration in B). (F and G) Mixed border cell cluster, wild-type, and shg mutant cells expressing DE-cadherinΔCyt/α-catenin. At stage 10, the cluster has reached the oocyte (F) or is delayed (G, incomplete migration). (H–K) Centripetal cell migration and direct comparison of mutant (green) with wild-type cells. shg mutant cells (H, early; and I, late) show defects; shg mutant cells expressing DE-cadherinΔCyt/α-catenin (J, early; and K, late) show no defect (n = 23). Phalloidin (red) stains F-actin and DAPI (blue) stains nuclei. GFP (green) marks wild-type cells in D and E and mutant cells in F–K. Bars (C), 20 μm; (D–G) 80 μm.

Mentions: If the migration defects that were observed in border cells expressing only DE-cadherinΔCyt/α-catenin were caused by a lack of adhesion down-regulation and, hence, an excess of adhesion, one would expect DE-cadherinΔCyt/α-catenin to behave in a dominant way. Border cell migration should be perturbed when DE-cadherinΔCyt/α-catenin is expressed in the presence of endogenous DE-cadherin and when half of the border cells in a cluster express only DE-cadherinΔCyt/α-catenin, whereas the other half express endogenous DE-cadherin. When DE-cadherinΔCyt/α-catenin was expressed in wild-type egg chambers in a manner similar to what was performed in the shg rescue experiment, it was targeted to the cell membrane (Fig. 5 C) but gave rise to only very mild migration defects (Fig. 5 A). In mixed border cell clusters in which half of the cells were wild type and the other half were shg mutant cells expressing DE-cadherinΔCyt/α-catenin, we observed mild delays (Fig. 5 B). This phenotype was similar to what was observed in shg mixed border cell clusters (half of the border cells were wild type and half were shg mutant; Fig. 5 B). In this latter situation, it is thought that shg mutant cells are pulled by the wild-type cells, explaining why most border cell clusters migrate normally (Niewiadomska et al., 1999). Thus, DE-cadherinΔCyt/α-catenin does not have a prominent dominant inhibitory effect during border cell migration, indicating that its inability to support migration is not simply caused by a lack of adhesion down-regulation.


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

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

Further analysis of DE-cadherinΔCyt/α-catenin phenotypes. (A) Migration defects of border cells expressing DE-cadherinΔCyt/α-catenin in shg mutant or wild-type background. (B) Migration defects of mixed border cell clusters. In each scored cluster, half of the border cells are wild type and half are as indicated (D–G). (C) DE-cadherin surface levels in wild-type cells expressing DE-cadherinΔCyt/α-catenin (below the green line). (D and E) Mixed border cell cluster, wild-type, and shg mutant cells. At stage 10, the full cluster has reached the oocyte (D), or shg mutant cells (E, arrow) are split from wild-type cells (E, arrowhead; incomplete migration in B). (F and G) Mixed border cell cluster, wild-type, and shg mutant cells expressing DE-cadherinΔCyt/α-catenin. At stage 10, the cluster has reached the oocyte (F) or is delayed (G, incomplete migration). (H–K) Centripetal cell migration and direct comparison of mutant (green) with wild-type cells. shg mutant cells (H, early; and I, late) show defects; shg mutant cells expressing DE-cadherinΔCyt/α-catenin (J, early; and K, late) show no defect (n = 23). Phalloidin (red) stains F-actin and DAPI (blue) stains nuclei. GFP (green) marks wild-type cells in D and E and mutant cells in F–K. Bars (C), 20 μm; (D–G) 80 μm.
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getmorefigures.php?uid=PMC2171345&req=5

fig5: Further analysis of DE-cadherinΔCyt/α-catenin phenotypes. (A) Migration defects of border cells expressing DE-cadherinΔCyt/α-catenin in shg mutant or wild-type background. (B) Migration defects of mixed border cell clusters. In each scored cluster, half of the border cells are wild type and half are as indicated (D–G). (C) DE-cadherin surface levels in wild-type cells expressing DE-cadherinΔCyt/α-catenin (below the green line). (D and E) Mixed border cell cluster, wild-type, and shg mutant cells. At stage 10, the full cluster has reached the oocyte (D), or shg mutant cells (E, arrow) are split from wild-type cells (E, arrowhead; incomplete migration in B). (F and G) Mixed border cell cluster, wild-type, and shg mutant cells expressing DE-cadherinΔCyt/α-catenin. At stage 10, the cluster has reached the oocyte (F) or is delayed (G, incomplete migration). (H–K) Centripetal cell migration and direct comparison of mutant (green) with wild-type cells. shg mutant cells (H, early; and I, late) show defects; shg mutant cells expressing DE-cadherinΔCyt/α-catenin (J, early; and K, late) show no defect (n = 23). Phalloidin (red) stains F-actin and DAPI (blue) stains nuclei. GFP (green) marks wild-type cells in D and E and mutant cells in F–K. Bars (C), 20 μm; (D–G) 80 μm.
Mentions: If the migration defects that were observed in border cells expressing only DE-cadherinΔCyt/α-catenin were caused by a lack of adhesion down-regulation and, hence, an excess of adhesion, one would expect DE-cadherinΔCyt/α-catenin to behave in a dominant way. Border cell migration should be perturbed when DE-cadherinΔCyt/α-catenin is expressed in the presence of endogenous DE-cadherin and when half of the border cells in a cluster express only DE-cadherinΔCyt/α-catenin, whereas the other half express endogenous DE-cadherin. When DE-cadherinΔCyt/α-catenin was expressed in wild-type egg chambers in a manner similar to what was performed in the shg rescue experiment, it was targeted to the cell membrane (Fig. 5 C) but gave rise to only very mild migration defects (Fig. 5 A). In mixed border cell clusters in which half of the cells were wild type and the other half were shg mutant cells expressing DE-cadherinΔCyt/α-catenin, we observed mild delays (Fig. 5 B). This phenotype was similar to what was observed in shg mixed border cell clusters (half of the border cells were wild type and half were shg mutant; Fig. 5 B). In this latter situation, it is thought that shg mutant cells are pulled by the wild-type cells, explaining why most border cell clusters migrate normally (Niewiadomska et al., 1999). Thus, DE-cadherinΔCyt/α-catenin does not have a prominent dominant inhibitory effect during border cell migration, indicating that its inability to support migration is not simply caused by a lack of adhesion down-regulation.

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