Rat protein tyrosine phosphatase eta physically interacts with the PDZ domains of syntenin

The tyrosine phosphatase r-PTP eta is able to suppress the malignant phenot ype of rat thyroid tumorigenic cell lines. To identify r-PTP eta interactin g proteins, a yeast two-hybrid screening was performed and an insert corres ponding to the full-length syntenin cDNA mas isolated. It encodes a protein containing two PDZ domains that mediates the binding of syntenin to protei ns such as syndecan, proTGF-alpha, beta -ephrins and neurofascin, We show t hat r-PTP eta is able to interact with syntenin also in mammalian cells, an d although syntenin is a tyrosine-phosphorylated protein it is not a substr ate of r-PTP eta. The integrity of both PDZ domains of syntenin and the car boxy-terminal region of r-PTP eta are required for the interaction between syntenin and r-PTP eta. (C) 2001 Published by Elsevier Science B,V. on beha lf of the Federation of European Biochemical Societies.