title: SHIP2 overexpression strongly reduces the proliferation rate of K562 erythroleukemia cell line.
abstract: SHIP2 belongs to the inositol 5-phosphatase family and is characterized by a phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P(3)) 5-phosphatase activity. Evidence based on mice lacking the SHIP2 gene has demonstrated its predominant role in the control of insulin sensitivity. However, SHIP2 expression in both hematopoietic and non-hematopoietic cells suggests additional functions. SHIP2 was previously identified in chronic myelogenous progenitor cells, in which its constitutive tyrosine phosphorylation was reported by Wisniewski et al., [Blood 93 (1999) 2707-2720]. Here, we further investigated the function of SHIP2 in this hematopoietic and malignant context. A detailed analysis of the substrate specificity of SHIP2 indicated that this phosphatase is primarily directed towards PI(3,4,5)P(3) both in vitro and in K562 chronic myeloid leukemia cells. The SHIP2-mediated decrease in PI(3,4,5)P(3) levels and increase in phosphatidylinositol 3,4-bisphosphate (PI(3,4)P(2)) was accompanied by a reduction of cell proliferation, characterized by an accumulation of the cells in the G2/M phase of the cell cycle. Thus, in addition to its role in the control of insulin sensitivity, SHIP2 may also play a role in cell proliferation, at least in chronic myelogenous progenitor cells.
authors.affiliation: Interdisciplinary Research Institute (IRIBHN), Université Libre de Bruxelles, Campus Erasme, 808 Route de Lennik, 1070, Brussels, Belgium.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Giuriato
authors.forename: Daniel
authors.initials: D
authors.lastname: Blero
authors.forename: Bernard
authors.initials: B
authors.lastname: Robaye
authors.forename: Catherine
authors.initials: C
authors.lastname: Bruyns
authors.forename: Bernard
authors.initials: B
authors.lastname: Payrastre
authors.forename: Christophe
authors.initials: C
authors.lastname: Erneux
mesh_terms: D015153:Blotting, Western; D002453:Cell Cycle; D002455:Cell Division; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D020014:K562 Cells; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D012333:RNA, Messenger; D010744:Phosphoric Monoester Hydrolases; C098706:INPPL1 protein, human; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases