title: p27kip1 controls cell morphology and motility by regulating microtubule-dependent lipid raft recycling.
abstract: p27(kip1) (p27) is an inhibitor of cyclin/cyclin-dependent kinase complexes, whose nuclear loss indicates a poor prognosis in various solid tumors. When located in the cytoplasm, p27 binds Op18/stathmin (stathmin), a microtubule (MT)-destabilizing protein, and restrains its activity. This leads to MT stabilization, which negatively affects cell migration. Here, we demonstrate that this p27 function also influences morphology and motility of cells immersed in three-dimensional (3D)matrices. Cells lacking p27 display a decrease in MT stability, a rounded shape when immersed in 3D environments, and a mesenchymal-amoeboid conversion in their motility mode. Upon cell contact to extracellular matrix, the decreased MT stability observed in p27 null cells results in accelerated lipid raft trafficking and increased RhoA activity. Importantly, cell morphology, motility, MT network composition, and distribution of p27 null cells were rescued by the concomitant genetic ablation of Stathmin, implicating that the balanced expression of p27 and stathmin represents a crucial determinant for cytoskeletal organization and cellular behavior in 3D contexts.
authors.affiliation: Division of Experimental Oncology 2, Centro di Riferimento Oncologico, National Cancer Institute, Via Franco Gallini, 2, 33081 Aviano, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Belletti
authors.forename: Ilenia
authors.initials: I
authors.lastname: Pellizzari
authors.forename: Stefania
authors.initials: S
authors.lastname: Berton
authors.forename: Linda
authors.initials: L
authors.lastname: Fabris
authors.forename: Katarina
authors.initials: K
authors.lastname: Wolf
authors.forename: Francesca
authors.initials: F
authors.lastname: Lovat
authors.forename: Monica
authors.initials: M
authors.lastname: Schiappacassi
authors.forename: Sara
authors.initials: S
authors.lastname: D'Andrea
authors.forename: Milena S
authors.initials: MS
authors.lastname: Nicoloso
authors.forename: Sara
authors.initials: S
authors.lastname: Lovisa
authors.forename: Maura
authors.initials: M
authors.lastname: Sonego
authors.forename: Paola
authors.initials: P
authors.lastname: Defilippi
authors.forename: Andrea
authors.initials: A
authors.lastname: Vecchione
authors.forename: Alfonso
authors.initials: A
authors.lastname: Colombatti
authors.forename: Peter
authors.initials: P
authors.lastname: Friedl
authors.forename: Gustavo
authors.initials: G
authors.lastname: Baldassarre
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002465:Cell Movement; D048430:Cell Shape; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000172:deficiency / Q000378:metabolism*; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology; D004705:Endocytosis; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D021962:Membrane Microdomains / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D008870:Microtubules / Q000378:metabolism*; D050777:Stathmin / Q000172:deficiency / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D050777:Stathmin; D050760:Cyclin-Dependent Kinase Inhibitor p27; D020742:rhoA GTP-Binding Protein