title: Unbalancing the phosphatidylinositol-4,5-bisphosphate-cofilin interaction impairs cell steering.
abstract: Cofilin is a key player in actin dynamics during cell migration. Its activity is regulated by (de)phosphorylation, pH, and binding to phosphatidylinositol-4,5-bisphosphate [PI(4,5)P(2)]. Here, we here use a human cofilin-1 (D122K) mutant with increased binding affinity for PI(4,5)P(2) and slower release from the plasma membrane to study the role of the PI(4,5)P(2)-cofilin interaction in migrating cells. In fibroblasts in a background of endogenous cofilin, D122K cofilin expression negatively affects cell turning frequency. In carcinoma cells with down-regulated endogenous cofilin, D122K cofilin neither rescues the drastic morphological defects nor restores the effects in cell turning capacity, unlike what has been reported for wild-type cofilin. In cofilin knockdown cells, D122K cofilin expression promotes outgrowth of an existing lamellipod in response to epidermal growth factor (EGF) but does not result in initiation of new lamellipodia. This indicates that, next to phospho- and pH regulation, the normal release kinetics of cofilin from PI(4,5)P(2) is crucial as a local activation switch for lamellipodia initiation and as a signal for migrating cells to change direction in response to external stimuli. Our results demonstrate that the PI(4,5)P(2) regulatory mechanism, that is governed by EGF-dependent phospholipase C activation, is a determinant for the spatial and temporal control of cofilin activation required for lamellipodia initiation.
authors.affiliation: Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium.
authors.forename: Shirley
authors.initials: S
authors.lastname: Leyman
authors.forename: Mazen
authors.initials: M
authors.lastname: Sidani
authors.forename: Laila
authors.initials: L
authors.lastname: Ritsma
authors.forename: Davy
authors.initials: D
authors.lastname: Waterschoot
authors.forename: Robert
authors.initials: R
authors.lastname: Eddy
authors.forename: Daisy
authors.initials: D
authors.lastname: Dewitte
authors.forename: Olivier
authors.initials: O
authors.lastname: Debeir
authors.forename: Christine
authors.initials: C
authors.lastname: Decaestecker
authors.forename: Joël
authors.initials: J
authors.lastname: Vandekerckhove
authors.forename: Jacco
authors.initials: J
authors.lastname: van Rheenen
authors.forename: Christophe
authors.initials: C
authors.lastname: Ampe
authors.forename: John
authors.initials: J
authors.lastname: Condeelis
authors.forename: Marleen
authors.initials: M
authors.lastname: Van Troys
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology*; D048430:Cell Shape; D051338:Cofilin 1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D011554:Pseudopodia / Q000378:metabolism; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D051338:Cofilin 1; D019269:Phosphatidylinositol 4,5-Diphosphate; D011993:Recombinant Fusion Proteins