title: Characterization of two SHP-2-associated binding proteins and potential substrates in hematopoietic cells.
abstract: Multiple studies have demonstrated an important role for the Src homology 2-containing tyrosine phosphatase 2 (SHP-2) in receptor tyrosine kinase-regulated cell proliferation and differentiation. Recent studies have identified potential SHP-2 substrates which mediate these effects. SHP-2 also is implicated in several cytokine receptor signaling pathways and in Bcr-Abl transformation. However, its precise role and targets in normal and abnormal hematopoietic cells remain to be determined. We identified two novel tyrosyl-phosphorylated proteins associated with SHP-2 in hematopoietic cells. The first, a 97-kDa cytosolic protein (p97), associates inducibly with SHP-2 upon cytokine stimulation and constitutively in Bcr-Abl-transformed cells. In contrast, p135, a 135-kDa transmembrane glycoprotein, forms a distinct complex with SHP-2, independent of cytokine stimulation or Bcr-Abl transformation. Far Western analysis reveals that SHP-2, via its Src homology 2 domains, can interact directly with either protein. In vitro dephosphorylation experiments, as well as transient transfection studies using wild type and mutant SHP-2 constructs, suggest that p97 and p135 also are SHP-2 substrates. Our results indicate that SHP-2 forms at least two separate complexes in hematopoietic cells and point to new potential SHP-2 targets.
authors.affiliation: Cancer Biology Program, Division of Hematology-Oncology, Department of Medicine, Beth Israel Hospital and Harvard Medical School, Boston, Massachusetts 02215, USA. hgu@bidmc.harvard.edu
authors.forename: H
authors.initials: H
authors.lastname: Gu
authors.forename: J D
authors.initials: JD
authors.lastname: Griffin
authors.forename: B G
authors.initials: BG
authors.lastname: Neel
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000032:analysis / Q000378:metabolism*; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology; D016044:Fusion Proteins, bcr-abl / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D054648:Protein Phosphatase 2; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D018909:src Homology Domains
chemical_list: D002352:Carrier Proteins; D016207:Cytokines; D047908:Intracellular Signaling Peptides and Proteins; D016044:Fusion Proteins, bcr-abl; D054648:Protein Phosphatase 2; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; C509248:Ptpn6 protein, mouse; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases