... duplication. Here, we show that the Rac1 guanine nucleotide exchange factor (GEF) Tiam1 localises to centrosomes during S-phase, where it is required for the maintenance of normal centriole number. Depletion of Tiam1 leads to an increase in centrosomal PLK4 and centriole overduplication, whereas...

... are thought to contribute to tumor development in aging tissues. We have shown that fibroblasts deficient in the Rac exchange factor Tiam1 promote invasion and metastasis of associated epithelial tumor cells. Here, we use a three-dimensional culture model of cellular invasiveness to outline several steps...

...Tomasz P. Rygiel; Alexander E. Mertens; Kristin Strumane; Rob van der Kammen; John G. Collard Tiam1 is a ubiquitously expressed activator of the small GTPase Rac. Previously, we found that Tiam1 knockout (KO) mice are resistant to DMBA-induced skin tumorigenicity, which correlated with increased...

... by fibrillar amyloid-beta peptide (Aβ) is associated with increased activity of Rac1/Cdc42 Rho GTPases. Rac1 upregulation involves the participation of Tiam1, a Rac guanine-nucleotide exchange factor, where Aβ exposure leads to Tiam1 activation by a Ca 2+ -dependent mechanism. These results point to Rho...

... and migration. Tiam1 (T lymphoma invasion and metastasis 1), a guanine nucleotide exchange factor that activates Rac, is an important regulator of cell shape and invasiveness in epithelial cells and fibroblasts. Overexpression of Tiam1 in metastatic melanoma cells converted the constitutive mesenchymal...