Serine phosphorylation-dependent association of the band 4.1-related protein-tyrosine phosphatase PTPH1 with 14-3-3beta protein.
PTPH1 is a human protein-tyrosine phosphatase with homology to the band 4.1 superfamily of cytoskeletal-associated proteins. PTPH1 was found to associate with 14-3-3beta using a yeast two-hybrid screen, and its interaction could be reconstituted in vitro using recombinant proteins. Examination of the interaction between 14-3-3beta and various deletion mutants of PTPH1 by two-hybrid tests suggested that the integrity of the PTP is important for this binding. Although both PTPH1 and Raf-1 form complexes with 14-3-3beta, they appear to do so independently. Binding of 14-3-3beta to PTPH1 in vitro was abolished by pretreating PTPH1 with potato acid phosphatase and was greatly enhanced by pretreating with Cdc25C-associated protein kinase. Thus the association between PTPH1 and 14-3-3beta is phosphorylation-dependent. Two novel motifs RSLS359VE and RVDS853EP in PTPH1 were identified as major 14-3-3beta-binding sites, both of which are distinct from the consensus binding motif RSXSXP recently found in Raf-1. Mutation of Ser359 and Ser853 to alanine significantly reduced the association between 14-3-3beta and PTPH1. Furthermore, association of PTPH1 and 14-3-3beta was detected in several cell lines and was regulated in response to extracellular signals. These results raise the possibility that 14-3-3beta may function as an adaptor molecule in the regulation of PTPH1 and may provide a link between serine/threonine and tyrosine phosphorylation-dependent signaling pathways.
SciCrunch is a data sharing and display platform. Anyone can create a custom portal where they can select searchable subsets of hundreds of data sources, brand their web pages and create their community. SciCrunch will push data updates automatically to all portals on a weekly basis. User communities can also add their own data to scicrunch, however this is not currently a free service.