The tumor suppressor PTEN is a phosphatase with sequence similarity to the cytoskeletal protein tensin. Here the cellular roles of PTEN were investigated. Overexpression of PTEN inhibited cell migration, whereas antisense PTEN enhanced migration. Integrin-mediated cell spreading and the formation of focal adhesions were down-regulated by wild-type PTEN but not by PTEN with an inactive phosphatase domain. PTEN interacted with the focal adhesion kinase FAK and reduced its tyrosine phosphorylation. Overexpression of FAK partially antagonized the effects of PTEN. Thus, PTEN phosphatase may function as a tumor suppressor by negatively regulating cell interactions with the extracellular matrix.

Current concepts of cell migration were established in regular two-dimensional (2D) cell culture, but the roles of topography are poorly understood for cells migrating in an oriented 3D fibrillar extracellular matrix (ECM). We use a novel micropatterning technique termed microphotopatterning (μPP) to identify functions for 1D fibrillar patterns in 3D cell migration. In striking contrast to 2D, cell migration in both 1D and 3D is rapid, uniaxial, independent of ECM ligand density, and dependent on myosin II contractility and microtubules (MTs). 1D and 3D migration are also characterized by an anterior MT bundle with a posterior centrosome. We propose that cells migrate rapidly through 3D fibrillar matrices by a 1D migratory mechanism not mimicked by 2D matrices.