期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2001
卷号：98
期号：12
页码：6593-6598
DOI：10.1073/pnas.041608698
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We used a genetic method, the yeast substrate-trapping system, to identify substrates for protein tyrosine phosphatases {zeta} (PTP{zeta}/RPTP{beta}). This method is based on the yeast two-hybrid system, with two essential modifications: conditional expression of protein tyrosine kinase v-src (active src) to tyrosine-phosphorylate the prey proteins and screening by using a substrate-trap mutant of PTP{zeta} (PTP{zeta}-D1902A) as bait. By using this system, several substrate candidates for PTP{zeta} were isolated. Among them, GIT1/Cat-1 (G protein-coupled receptor kinase-interactor 1/Cool-associated, tyrosine-phosphorylated 1) was examined further. GIT1/Cat-1 bound to PTP{zeta}-D1902A dependent on the substrate tyrosine phosphorylation. Tyrosine-phosphorylated GIT1/Cat-1 was dephosphorylated by PTP{zeta} in vitro. Immunoprecipitation experiments indicated that PTP{zeta}-D1902A and GIT1/Cat-1 form a stable complex also in mammalian cells. Immunohistochemical analyses revealed that PTP{zeta} and GIT1/Cat-1 were colocalized in the processes of pyramidal cells in the hippocampus and neocortex in rat brain. Subcellular colocalization was further verified in the growth cones of mossy fibers from pontine explants and in the ruffling membranes and processes of B103 neuroblastoma cells. Moreover, pleiotrophin, a ligand for PTP{zeta
