title: A specific PTPRC/CD45 phosphorylation event governed by stem cell chemokine CXCL12 regulates primitive hematopoietic cell motility.
abstract: CXCL12 governs cellular motility, a process deregulated by hematopoietic stem cell oncogenes such as p210-BCR-ABL. A phosphoproteomics approach to the analysis of a hematopoietic progenitor cell line treated with CXCL12 and the Rac 1 and 2 inhibitor NSC23766 has been employed to objectively discover novel mechanisms for regulation of stem cells in normal and malignant hematopoiesis. The proteomic data sets identified new aspects of CXCL12-mediated signaling and novel features of stem cell regulation. We also identified a novel phosphorylation event in hematopoietic progenitor cells that correlated with motile response and governed by the chemotactic factor CXCL12. The novel phosphorylation site on PTPRC/CD45; a protein tyrosine phosphatase, was validated by raising an antibody to the site and also using a mass spectrometry absolute quantification strategy. Site directed mutagenesis and inhibitor studies demonstrated that this single phosphorylation site governs hematopoietic progenitor cell and lymphoid cell motility, lies downstream from Rac proteins and potentiates Src signaling. We have also demonstrated that PTPRC/CD45 is down-regulated in leukemogenic tyrosine kinase expressing cells. The use of discovery proteomics has enabled further understanding of the regulation of PTPRC/CD45 and its important role in cellular motility in progenitor cells.
authors.affiliation: Stem Cell and Leukaemia Proteomics Laboratory, School of Cancer and Enabling Sciences, Manchester Academic Health Science Centre, University of Manchester, 27 Palatine Rd, Manchester, M20 4QL;
authors.forename: Andrew J K
authors.initials: AJ
authors.lastname: Williamson
authors.forename: Andrew
authors.initials: A
authors.lastname: Pierce
authors.forename: Ewa
authors.initials: E
authors.lastname: Jaworska
authors.forename: Cong
authors.initials: C
authors.lastname: Zhou
authors.forename: Mark
authors.initials: M
authors.lastname: Aspinall-O'Dea
authors.forename: Lee
authors.initials: L
authors.lastname: Lancashire
authors.forename: Richard D
authors.initials: RD
authors.lastname: Unwin
authors.forename: Sheela A
authors.initials: SA
authors.lastname: Abraham
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Walker
authors.forename: Sara
authors.initials: S
authors.lastname: Cadecco
authors.forename: Elaine
authors.initials: E
authors.lastname: Spooncer
authors.forename: Tessa L
authors.initials: TL
authors.lastname: Holyoake
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Whetton
mesh_terms: D000634:Aminoquinolines / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D054377:Chemokine CXCL12 / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016044:Fusion Proteins, bcr-abl / Q000235:genetics / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D017493:Leukocyte Common Antigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010766:Phosphorylation; D040901:Proteomics; D011743:Pyrimidines / Q000494:pharmacology; D015398:Signal Transduction
chemical_list: D000634:Aminoquinolines; D054377:Chemokine CXCL12; C515256:Cxcl12 protein, mouse; D004791:Enzyme Inhibitors; C487513:NSC 23766; D011743:Pyrimidines; D016044:Fusion Proteins, bcr-abl; D017493:Leukocyte Common Antigens; C516769:PTPRC protein, human; C516770:Ptprc protein, mouse