Vinculin acts as a sensor in lipid regulation of adhesion-site turnover.
The dynamics of cell adhesion sites control cell morphology and motility. Adhesion-site turnover is thought to depend on the local availability of the acidic phospholipid phosphatidylinositol-4,5-bisphosphate (PIP(2)). PIP(2) can bind to many cell adhesion proteins such as vinculin and talin, but the consequences of this interaction are poorly understood. To study the significance of phospholipid binding to vinculin for adhesion-site turnover and cell motility, we constructed a mutant, vinculin-LD, deficient in acidic phospholipid binding yet with functional actin-binding sites. When expressed in cells, vinculin-LD was readily recruited to adhesion sites, as judged by fluorescence recovery after photobleaching (FRAP) analysis, but cell spreading and migration were strongly impaired, and PIP(2)-dependent disassembly of adhesions was suppressed. Thus, PIP(2) binding is not essential for vinculin activation and recruitment, as previously suggested. Instead, we propose that PIP(2) levels can regulate the uncoupling of adhesion sites from the actin cytoskeleton, with vinculin functioning as a sensor.
Chandrasekar
Indra
I
Cell Biology, Zoological Institute, Technical University of Braunschweig, 38106 Braunschweig, Germany.
Stradal
Theresia E B
TE
Holt
Mark R
MR
Entschladen
Frank
F
Jockusch
Brigitte M
BM
Ziegler
Wolfgang H
WH
D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002448:Cell Adhesion / Q000502:physiology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D003001:Cloning, Molecular; D003094:Collagen / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D036681:Fluorescence Recovery After Photobleaching; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008024:Ligands; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D016596:Vinculin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D008024:Ligands; D019269:Phosphatidylinositol 4,5-Diphosphate; D016596:Vinculin; D049452:Green Fluorescent Proteins; D003094:Collagen; D017853:Phosphotransferases (Alcohol Group Acceptor); C020077:1-phosphatidylinositol-4-phosphate 5-kinase