Our search for protein tyrosine phosphatases (PTPases) that are involved in murine development led to the isolation of a novel PTPase called MPTP-PEST. To elucidate the function of MPTP-PEST, several biological aspects of the protein were investigated. It was determined that the MPTP-PEST enzyme is a stable cytosolic protein tyrosine phosphatase of 112 kDa that is ubiquitously expressed both in the adult and in the embryo. MPTP-PEST is composed of a single amino-terminus catalytic domain which is active against phosphorylated substrates in vitro. The gene structure and chromosomal localization of MPTP-PEST were determined using a series of $ lambda$ phage clones isolated from a mouse genomic library. Analysis of the MPTP-PEST locus indicated that the gene spans over 90 kb of the mouse genome and is composed of 18 exons, 10 of which constitute the catalytic phosphatase domain. Fluorescence in situ hybridization with MPTP-PEST genomic DNA defines the map position of MPTP-PEST to mouse chromosome 5 region A3-B. To gain mechanistic insights into the function of MPTP-PEST, the association of proteins with MPTP-PEST was investigated using several different in vitro and in vivo binding assays. It was shown that the proto-oncoprotein SHC and the adaptor protein Grb2 associate with MPTP-PEST through specific carboxy-terminus sequences. In addition, the SHC/MPTP-PEST association was shown to be mediated by a novel type of protein-protein interaction. Both SHC and Grb2 function downstream of receptor type and cyloplasmic protein tyrosine kinases and have been shown to mediate several signal transduction events. The association of MPTP-PEST with these signaling proteins may therefore represent a function for MPTP-PEST in signaling events.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.42001 |
| Date | January 1996 |
| Creators | Charest, Alain. |
| Contributors | Tremblay, Michel (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Biochemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001549379, proquestno: NQ29908, Theses scanned by UMI/ProQuest. |
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