title: Reversible phosphorylation in haematological malignancies: potential role for protein tyrosine phosphatases in treatment?
abstract: Most aspects of leukocyte physiology are under the control of reversible tyrosine phosphorylation. It is clear that excessive phosphorylation of signal transduction elements is a pivotal element of many different pathologies including haematological malignancies and accordingly, strategies that target such phosphorylation have clinically been proven highly successful for treatment of multiple types of leukemias and lymphomas. Cellular phosphorylation status is dependent on the resultant activity of kinases and phosphatases. The cell biology of the former is now well understood; for most cellular phosphoproteins we now know the kinases responsible for their phosphorylation and we understand the principles of their aberrant activity in disease. With respect to phosphatases, however, our knowledge is much patchier. Although the sequences of whole genomes allow us to identify phosphatases using in silico methodology, whereas transcription profiling allows us to understand how phosphatase expression is regulated during disease, most functional questions as to substrate specificity, dynamic regulation of phosphatase activity and potential for therapeutic intervention are still to a large degree open. Nevertheless, recent studies have allowed us to make meaningful statements on the role of tyrosine phosphatase activity in the three major signaling pathways that are commonly affected in leukemias, i.e. the Ras-Raf-ERK1/2, the Jak-STAT and the PI3K-PKB-mTOR pathways. Lessons learned from these pathways may well be applicable elsewhere in leukocyte biology as well.
authors.affiliation: Center for Experimental and Molecular Medicine, Academic Medical Center, Meibergdreef 9 1105 AZ Amsterdam, The Netherlands.
authors.forename: Roberta R
authors.initials: RR
authors.lastname: Ruela-de-Sousa
authors.forename: Karla C S
authors.initials: KC
authors.lastname: Queiroz
authors.forename: Maikel P
authors.initials: MP
authors.lastname: Peppelenbosch
authors.forename: Gwenny M
authors.initials: GM
authors.lastname: Fuhler
mesh_terms: D000818:Animals; D019337:Hematologic Neoplasms / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism; D006801:Humans; D017493:Leukocyte Common Antigens / Q000502:physiology; D051059:PTEN Phosphohydrolase / Q000502:physiology; D010766:Phosphorylation; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000502:physiology; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000502:physiology; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000502:physiology; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D017493:Leukocyte Common Antigens; C516607:PTPN1 protein, human; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; D051059:PTEN Phosphohydrolase