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

The tyrosine phosphatase r-PTP eta is able to suppress the malignant phenotype of rat thyroid tumorigenic cell lines. To identify r-PTP eta interacting proteins, a yeast two-hybrid screening was performed and an insert corresponding to the full-length syntenin cDNA mas isolated. It encodes a protein containing two PDZ domains that mediates the binding of syntenin to proteins such as syndecan, proTGF-alpha, beta -ephrins and neurofascin, We show that r-PTP eta is able to interact with syntenin also in mammalian cells, and although syntenin is a tyrosine-phosphorylated protein it is not a substrate of r-PTP eta. The integrity of both PDZ domains of syntenin and the carboxy-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 behalf of the Federation of European Biochemical Societies.