TY - JOUR
T1 - Phosphatidylinositol-4,5 bisphosphate produced by PIP5KIγ regulates gelsolin, actin assembly, and adhesion strength of N-cadherin junctions
AU - El Sayegh, T. Y.
AU - Arora, P. D.
AU - Ling, K.
AU - Laschinger, C.
AU - Janmey, P. A.
AU - Anderson, R. A.
AU - McCulloch, C. A.
PY - 2007/8
Y1 - 2007/8
N2 - Phosphoinositides regulate several actin-binding proteins but their role at intercellular adhesions has not been defined. We found that phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) was generated at sites of N-cadherin-mediated intercellular adhesion and was a critical regulator of intercellular adhesion strength. Immunostaining for PI(4,5)P2 or transfection with GFP-PH-PLCδ showed that PI(4,5)P2 was enriched at sites of N-cadherin adhesions and this enrichment required activated Rac1. Isoform-specific immunostaining for type I phosphatidylinositol 4-phosphate 5 kinase (PIP5KI) showed that PIP5KIγ was spatially associated with N-cadherin-Fc beads. Association of PIP5KIγ with N-cadherin adhesions was in part dependent on the activation of RhoA. Transfection with catalytically inactive PIP5KIγ blocked the enrichment of PI(4,5)P 2 around beads. Catalytically inactive PIP5KIγ or a cell-permeant peptide that mimics and competes for the PI(4,5)P 2-binding region of the actin-binding protein gelsolin inhibited incorporation of actin monomers in response to N-cadherin ligation and reduced intercellular adhesion strength by more than twofold. Gelsolin null fibroblasts transfected with a gelsolin severing mutant containing an intact PI(4,5)P 2 binding region, demonstrated intercellular adhesion strength similar to wild-type transfected controls. We conclude that PIP5KIγ- mediated generation of PI(4,5)P2 at sites of N-cadherin contacts regulates intercellular adhesion strength, an effect due in part to PI(4,5)P2-mediated regulation of gelsolin.
AB - Phosphoinositides regulate several actin-binding proteins but their role at intercellular adhesions has not been defined. We found that phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) was generated at sites of N-cadherin-mediated intercellular adhesion and was a critical regulator of intercellular adhesion strength. Immunostaining for PI(4,5)P2 or transfection with GFP-PH-PLCδ showed that PI(4,5)P2 was enriched at sites of N-cadherin adhesions and this enrichment required activated Rac1. Isoform-specific immunostaining for type I phosphatidylinositol 4-phosphate 5 kinase (PIP5KI) showed that PIP5KIγ was spatially associated with N-cadherin-Fc beads. Association of PIP5KIγ with N-cadherin adhesions was in part dependent on the activation of RhoA. Transfection with catalytically inactive PIP5KIγ blocked the enrichment of PI(4,5)P 2 around beads. Catalytically inactive PIP5KIγ or a cell-permeant peptide that mimics and competes for the PI(4,5)P 2-binding region of the actin-binding protein gelsolin inhibited incorporation of actin monomers in response to N-cadherin ligation and reduced intercellular adhesion strength by more than twofold. Gelsolin null fibroblasts transfected with a gelsolin severing mutant containing an intact PI(4,5)P 2 binding region, demonstrated intercellular adhesion strength similar to wild-type transfected controls. We conclude that PIP5KIγ- mediated generation of PI(4,5)P2 at sites of N-cadherin contacts regulates intercellular adhesion strength, an effect due in part to PI(4,5)P2-mediated regulation of gelsolin.
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U2 - 10.1091/mbc.E06-12-1159
DO - 10.1091/mbc.E06-12-1159
M3 - Article
C2 - 17538019
AN - SCOPUS:34547796327
SN - 1059-1524
VL - 18
SP - 3026
EP - 3038
JO - Molecular biology of the cell
JF - Molecular biology of the cell
IS - 8
ER -