title: Nuclear translocation of immulectin-3 stimulates hemocyte proliferation.
abstract: Immulectin-3 (IML-3) is a C-type lectin from the tobacco hornworm Manduca sexta that contains a motif (NWGV) similar to the BH1 motif (NWGR) of the mammalian galectin-3. IML-3 is synthesized in fat body and secreted into hemolymph, but can be translocated into hemocytes. In this study, we showed that IML-3 was predominantly localized to the nucleus of hemocytes and some metaphase, anaphase and telophase hemocytes from M. sexta larvae injected with bacterial lipopolysaccharide (LPS). IML-3 was detected in the membrane and soluble extracts of hemocytes, suggesting that it may be translocated into hemocytes via receptor-mediated endocytosis. To investigate the role of IML-3 translocation to the nucleus, we expressed recombinant wild-type IML-3 and a deletion mutant DeltaIML-3 that has the NWGV motif deleted in Drosophila S2 cells. We found that recombinant wild-type IML-3, but not DeltaIML-3, was localized to the nucleus of some S2 cells and also detected in the nuclear extract. Expression of recombinant wild-type IML-3, but not DeltaIML-3 or GFP, increased the number of proliferating S2 cells. Our results suggest that nuclear translocation of IML-3 may stimulate hemocyte proliferation.
authors.affiliation: School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
authors.forename: Erjun
authors.initials: E
authors.lastname: Ling
authors.forename: Jingqun
authors.initials: J
authors.lastname: Ao
authors.forename: Xiao-Qiang
authors.initials: XQ
authors.lastname: Yu
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D002467:Cell Nucleus / Q000276:immunology / Q000378:metabolism*; D049109:Cell Proliferation; D004705:Endocytosis; D006434:Hemocytes / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D006458:Hemolymph / Q000276:immunology / Q000378:metabolism; D019476:Insect Proteins / Q000276:immunology / Q000378:metabolism*; D007814:Larva / Q000166:cytology / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D037181:Lectins, C-Type / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000276:immunology; D018402:Manduca / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D050505:Mutant Proteins / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism
chemical_list: D019476:Insect Proteins; D037181:Lectins, C-Type; D008070:Lipopolysaccharides; D050505:Mutant Proteins; D011994:Recombinant Proteins; C121403:immulectin, Manduca sexta