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Dual regulation of neuronal morphogenesis by a delta-catenin-cortactin complex and Rho.

Martinez MC, Ochiishi T, Majewski M, Kosik KS - J. Cell Biol. (2003)

Bottom Line: Under conditions when tyrosine phosphorylation is reduced, delta-catenin binds to cortactin and cells extend unbranched primary processes.When RhoA is inhibited, delta-catenin enhances the effects of Rho inhibition on branching.We conclude that delta-catenin contributes to setting a balance between neurite elongation and branching in the elaboration of a complex dendritic tree.

View Article: PubMed Central - PubMed

Affiliation: Dept. of Neurology, Brigham and Women's Hospital and Harvard Medical School, Harvard Institute of Medicine, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.

ABSTRACT
Delta-catenin is a neuronal protein that contains 10 Armadillo motifs and binds to the juxtamembrane segment of classical cadherins. We report that delta-catenin interacts with cortactin in a tyrosine phosphorylation-dependent manner. This interaction occurs within a region of the delta-catenin sequence that is also essential for the neurite elongation effects. Src family kinases can phosphorylate delta-catenin and bind to delta-catenin through its polyproline tract. Under conditions when tyrosine phosphorylation is reduced, delta-catenin binds to cortactin and cells extend unbranched primary processes. Conversely, increasing tyrosine phosphorylation disrupts the delta-catenin-cortactin complex. When RhoA is inhibited, delta-catenin enhances the effects of Rho inhibition on branching. We conclude that delta-catenin contributes to setting a balance between neurite elongation and branching in the elaboration of a complex dendritic tree.

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Tyrosine phosphorylation of δ-catenin. (A) δ-PC12 cells (pretreated with NGF for 36 h) and hippocampal neurons were treated with 25 μm PP2 for 1 h; additionally, hippocampal neurons were treated with 200 μM H2O2 for 5 min, δ-catenin was immuno- precipitated with a mAb δ-catenin, and its phosphorylation state was tested with antiphosphotyrosine. (B) δ-PC12 cells were transfected with constructs corresponding to Fyn or a dominant-negative Fyn (FynK299M). Cells were lysed, and lysates were subjected to immunoprecipitation with a mAb δ-catenin. The immunocomplexes were sequentially immunoblotted with a mAb δ-catenin and a phospho- tyrosine antibody. (C) In the top panel, COS 1 cells were transfected with FLδ or FLδΔP6. Cell lysates were incubated with GST–SH3Lck and GST–SH3Fyn fusion proteins bound to glutathione-sepharose beads. Lysates incubated with glutathione beads alone served as a control. In the bottom panel, GST–SH3Lck and GST–SH3Fyn fusion proteins bound to glutathione sepharose beads, or beads alone were incubated with lysates from 3-wk-old hippocampal neurons. In all lanes, eluted proteins were blotted with a mAb δ-catenin.
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fig7: Tyrosine phosphorylation of δ-catenin. (A) δ-PC12 cells (pretreated with NGF for 36 h) and hippocampal neurons were treated with 25 μm PP2 for 1 h; additionally, hippocampal neurons were treated with 200 μM H2O2 for 5 min, δ-catenin was immuno- precipitated with a mAb δ-catenin, and its phosphorylation state was tested with antiphosphotyrosine. (B) δ-PC12 cells were transfected with constructs corresponding to Fyn or a dominant-negative Fyn (FynK299M). Cells were lysed, and lysates were subjected to immunoprecipitation with a mAb δ-catenin. The immunocomplexes were sequentially immunoblotted with a mAb δ-catenin and a phospho- tyrosine antibody. (C) In the top panel, COS 1 cells were transfected with FLδ or FLδΔP6. Cell lysates were incubated with GST–SH3Lck and GST–SH3Fyn fusion proteins bound to glutathione-sepharose beads. Lysates incubated with glutathione beads alone served as a control. In the bottom panel, GST–SH3Lck and GST–SH3Fyn fusion proteins bound to glutathione sepharose beads, or beads alone were incubated with lysates from 3-wk-old hippocampal neurons. In all lanes, eluted proteins were blotted with a mAb δ-catenin.

Mentions: To determine the family of tyrosine kinases responsible for phosphorylating δ-catenin, δ-PC12 cells were treated with several tyrosine kinase inhibitors. We found that a treatment with PP2 (25 μM), a Fyn/Lck/Hck tyrosine kinase inhibitor (Fig. 7Figure 7.


Dual regulation of neuronal morphogenesis by a delta-catenin-cortactin complex and Rho.

Martinez MC, Ochiishi T, Majewski M, Kosik KS - J. Cell Biol. (2003)

Tyrosine phosphorylation of δ-catenin. (A) δ-PC12 cells (pretreated with NGF for 36 h) and hippocampal neurons were treated with 25 μm PP2 for 1 h; additionally, hippocampal neurons were treated with 200 μM H2O2 for 5 min, δ-catenin was immuno- precipitated with a mAb δ-catenin, and its phosphorylation state was tested with antiphosphotyrosine. (B) δ-PC12 cells were transfected with constructs corresponding to Fyn or a dominant-negative Fyn (FynK299M). Cells were lysed, and lysates were subjected to immunoprecipitation with a mAb δ-catenin. The immunocomplexes were sequentially immunoblotted with a mAb δ-catenin and a phospho- tyrosine antibody. (C) In the top panel, COS 1 cells were transfected with FLδ or FLδΔP6. Cell lysates were incubated with GST–SH3Lck and GST–SH3Fyn fusion proteins bound to glutathione-sepharose beads. Lysates incubated with glutathione beads alone served as a control. In the bottom panel, GST–SH3Lck and GST–SH3Fyn fusion proteins bound to glutathione sepharose beads, or beads alone were incubated with lysates from 3-wk-old hippocampal neurons. In all lanes, eluted proteins were blotted with a mAb δ-catenin.
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Related In: Results  -  Collection

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fig7: Tyrosine phosphorylation of δ-catenin. (A) δ-PC12 cells (pretreated with NGF for 36 h) and hippocampal neurons were treated with 25 μm PP2 for 1 h; additionally, hippocampal neurons were treated with 200 μM H2O2 for 5 min, δ-catenin was immuno- precipitated with a mAb δ-catenin, and its phosphorylation state was tested with antiphosphotyrosine. (B) δ-PC12 cells were transfected with constructs corresponding to Fyn or a dominant-negative Fyn (FynK299M). Cells were lysed, and lysates were subjected to immunoprecipitation with a mAb δ-catenin. The immunocomplexes were sequentially immunoblotted with a mAb δ-catenin and a phospho- tyrosine antibody. (C) In the top panel, COS 1 cells were transfected with FLδ or FLδΔP6. Cell lysates were incubated with GST–SH3Lck and GST–SH3Fyn fusion proteins bound to glutathione-sepharose beads. Lysates incubated with glutathione beads alone served as a control. In the bottom panel, GST–SH3Lck and GST–SH3Fyn fusion proteins bound to glutathione sepharose beads, or beads alone were incubated with lysates from 3-wk-old hippocampal neurons. In all lanes, eluted proteins were blotted with a mAb δ-catenin.
Mentions: To determine the family of tyrosine kinases responsible for phosphorylating δ-catenin, δ-PC12 cells were treated with several tyrosine kinase inhibitors. We found that a treatment with PP2 (25 μM), a Fyn/Lck/Hck tyrosine kinase inhibitor (Fig. 7Figure 7.

Bottom Line: Under conditions when tyrosine phosphorylation is reduced, delta-catenin binds to cortactin and cells extend unbranched primary processes.When RhoA is inhibited, delta-catenin enhances the effects of Rho inhibition on branching.We conclude that delta-catenin contributes to setting a balance between neurite elongation and branching in the elaboration of a complex dendritic tree.

View Article: PubMed Central - PubMed

Affiliation: Dept. of Neurology, Brigham and Women's Hospital and Harvard Medical School, Harvard Institute of Medicine, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.

ABSTRACT
Delta-catenin is a neuronal protein that contains 10 Armadillo motifs and binds to the juxtamembrane segment of classical cadherins. We report that delta-catenin interacts with cortactin in a tyrosine phosphorylation-dependent manner. This interaction occurs within a region of the delta-catenin sequence that is also essential for the neurite elongation effects. Src family kinases can phosphorylate delta-catenin and bind to delta-catenin through its polyproline tract. Under conditions when tyrosine phosphorylation is reduced, delta-catenin binds to cortactin and cells extend unbranched primary processes. Conversely, increasing tyrosine phosphorylation disrupts the delta-catenin-cortactin complex. When RhoA is inhibited, delta-catenin enhances the effects of Rho inhibition on branching. We conclude that delta-catenin contributes to setting a balance between neurite elongation and branching in the elaboration of a complex dendritic tree.

Show MeSH