Physical and functional interactions between type I transforming growth factor beta receptors and Balpha, a WD-40 repeat subunit of phosphatase 2A

• Published in: Molecular and cellular biology 1998-11, Vol.18 (11), p.6595
• Main Authors: Griswold-Prenner, I, Kamibayashi, C, Maruoka, E M, Mumby, M C, Derynck, R
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Activin Receptors, Type I; Animals; Cell Division - physiology; Cross-Linking Reagents - metabolism; Cyclin A - metabolism; Gene Expression Regulation, Enzymologic - genetics; Genes, Reporter; Membrane Proteins - metabolism; Mice; Phosphoprotein Phosphatases - chemistry; Phosphorylation; Protein Kinases - metabolism; Protein Phosphatase 2; Protein Serine-Threonine Kinases - metabolism; Receptor, Transforming Growth Factor-beta Type I; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta - metabolism; Recombinant Fusion Proteins - metabolism; Signal Transduction - physiology
• ISSN: 0270-7306
• DOI: 10.1128/MCB.18.11.6595

We have previously shown that a WD-40 repeat protein, TRIP-1, associates with the type II transforming growth factor beta (TGF-beta) receptor. In this report, we show that another WD-40 repeat protein, the Balpha subunit of protein phosphatase 2A, associates with the cytoplasmic domain of type I TGF-beta receptors. This association depends on the kinase activity of the type I receptor, is increased by coexpression of the type II receptor, which is known to phosphorylate and activate the type I receptor, and allows the type I receptor to phosphorylate Balpha. Furthermore, Balpha enhances the growth inhibition activity of TGF-beta in a receptor-dependent manner. Because Balpha has been characterized as a regulator of phosphatase 2A activity, our observations suggest possible functional interactions between the TGF-beta receptor complex and the regulation of protein phosphatase 2A.