title: Evidence that the lipid phosphatase SHIP-1 regulates T lymphocyte morphology and motility.
abstract: SHIP-1 negatively regulates the PI3K pathway in hematopoietic cells and has an emerging role in T lymphocyte biology. PI3K and SHIP can regulate cell migration in leukocytes, particularly in neutrophils, although their role in T cell migration has been less clear. Therefore, we sought to explore the role of SHIP-1 in human CD4(+) T lymphocyte cell migration responses to chemoattractants using a lentiviral-mediated expression system and a short hairpin RNA approach. Silencing of SHIP-1 leads to increased basal phosphorylation of protein kinase B/Akt and its substrate GSK3β, as well as an increase in basal levels of polymerized actin, suggesting that SHIP-1 might regulate changes in the cytoskeleton. Accordingly, silencing of SHIP-1 led to loss of microvilli and ezrin/radixin/moesin phosphorylation, which could not be rescued by the PI3K inhibitor Ly294002. There were striking morphological changes, including a loss of microvilli projections, which mirrored changes in wild type cells after stimulation with the chemokine CXCL11. There was no defect in directional T cell migration toward CXCL11 in the SHIP-1-silenced cells but, importantly, there was a defect in the overall basal motility of SHIP-1 knockdown cells. Taken together, these results implicate SHIP-1 as a key regulator of basal PI3K signaling in human CD4(+) T lymphocytes with important phosphatase-independent actions, which together are key for maintaining normal morphology and basal motility.
authors.affiliation: Inflammatory Cell Biology Laboratory, Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, United Kingdom.
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Harris
authors.forename: Richard V
authors.initials: RV
authors.lastname: Parry
authors.forename: John G
authors.initials: JG
authors.lastname: Foster
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Blunt
authors.forename: Amu
authors.initials: A
authors.lastname: Wang
authors.forename: Federica
authors.initials: F
authors.lastname: Marelli-Berg
authors.forename: John
authors.initials: J
authors.lastname: Westwick
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Ward
mesh_terms: D000199:Actins / Q000378:metabolism; D015153:Blotting, Western; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D002465:Cell Movement; D002470:Cell Survival; D002478:Cells, Cultured; D054371:Chemokine CXCL11 / Q000494:pharmacology; D003598:Cytoskeletal Proteins / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D005434:Flow Cytometry; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D000072181:Inositol Polyphosphate 5-Phosphatases; D008565:Membrane Proteins / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D008871:Microvilli / Q000378:metabolism / Q000648:ultrastructure; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010716:Phosphatidylinositols / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034622:RNA Interference; D015398:Signal Transduction; D000099149:Ezrin
chemical_list: D000199:Actins; D054371:Chemokine CXCL11; D003598:Cytoskeletal Proteins; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D000072181:Inositol Polyphosphate 5-Phosphatases; D008565:Membrane Proteins; D008840:Microfilament Proteins; D019869:Phosphatidylinositol 3-Kinases; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010716:Phosphatidylinositols; D010744:Phosphoric Monoester Hydrolases; D051057:Proto-Oncogene Proteins c-akt; D000099149:Ezrin; C118303:phosphoinositide-3,4,5-triphosphate; C071058:moesin; C071776:radixin; C000605506:GSK3B protein, human; C000606430:INPP5D protein, human