APC and Smad7 link TGFβ type I receptors to the microtubule system to promote cell migration

• Published in: Molecular biology of the cell 2012-06, Vol.23 (11), p.2109-2121
• Main Authors: Ekman, Maria, Mu, Yabing, Lee, So Young, Edlund, Sofia, Kozakai, Takaharu, Thakur, Noopur, Tran, Hoanh, Qian, Jiang, Groeden, Joanna, Heldin, Carl-Henrik, Landström, Maréne
• Format: Article
• Language: English
• Subjects: Actin Cytoskeleton - drug effects; Actin Cytoskeleton - metabolism; ACTIVATION; Adenomatous Polyposis Coli Protein - metabolism; ADENOMATOUS POLYPOSIS-COLI; Animals; APC; APOPTOSIS; beta Catenin - metabolism; CANCER; CATENIN; Cell Line, Tumor; cell migration; Cell Movement - drug effects; Cell Polarity - drug effects; Cell Research; Cellforskning; E-CADHERIN; Enzyme Activation - drug effects; Glycogen Synthase Kinase 3 - metabolism; Glycogen Synthase Kinase 3 beta; GROWTH-FACTOR-BETA; GSK-3beta; Humans; KINASE; Male; Mice; Microtubules - drug effects; Microtubules - metabolism; Models, Biological; p38; p38 Mitogen-Activated Protein Kinases - metabolism; Prostatic Neoplasms - enzymology; Prostatic Neoplasms - pathology; PROSTATIC-CARCINOMA CELLS; PROTEIN; Protein Binding - drug effects; Protein-Serine-Threonine Kinases - metabolism; Pseudopodia - drug effects; Pseudopodia - metabolism; Receptors, Transforming Growth Factor beta - metabolism; Smad7; Smad7 Protein - metabolism; TGF-beta; Transforming Growth Factor beta - pharmacology
• ISSN: 1059-1524; 1939-4586; 1939-4586
• DOI: 10.1091/mbc.E10-12-1000

Cell migration occurs by activation of complex regulatory pathways that are spatially and temporally integrated in response to extracellular cues. Binding of adenomatous polyposis coli (APC) to the microtubule plus ends in polarized cells is regulated by glycogen synthase kinase 3β (GSK-3β). This event is crucial for establishment of cell polarity during directional migration. However, the role of APC for cellular extension in response to extracellular signals is less clear. Smad7 is a direct target gene for transforming growth factor-β (TGFβ) and is known to inhibit various TGFβ-induced responses. Here we report a new function for Smad7. We show that Smad7 and p38 mitogen-activated protein kinase together regulate the expression of APC and cell migration in prostate cancer cells in response to TGFβ stimulation. In addition, Smad7 forms a complex with APC and acts as an adaptor protein for p38 and GSK-3β kinases to facilitate local TGFβ/p38-dependent inactivation of GSK-3β, accumulation of β-catenin, and recruitment of APC to the microtubule plus end in the leading edge of migrating prostate cancer cells. Moreover, the Smad7-APC complex links the TGFβ type I receptor to the microtubule system to regulate directed cellular extension and migratory responses evoked by TGFβ.