title: Cell surface expression of channel catfish leukocyte immune-type receptors (IpLITRs) and recruitment of both Src homology 2 domain-containing protein tyrosine phosphatase (SHP)-1 and SHP-2.
abstract: Channel catfish leukocyte immune-type receptors (IpLITRs) are immunoglobulin superfamily (IgSF) members believed to play a role in the control and coordination of cellular immune responses in teleost. Putative stimulatory and inhibitory IpLITRs are co-expressed by different types of catfish immune cells (e.g. NK cells, T cells, B cells, and macrophages) but their signaling potential has not been determined. Following cationic polymer-mediated transfections into human cell lines we examined the surface expression, tyrosine phosphorylation, and phosphatase recruitment potential of two types of putative inhibitory IpLITRs using 'chimeric' expression constructs and an epitope-tagged 'native' IpLITR. We also cloned and expressed the teleost Src homology 2 domain-containing protein tyrosine phosphatases (SHP)-1 and SHP-2 and examined their expression in adult tissues and developing zebrafish embryos. Co-immunoprecipitation experiments support the inhibitory signaling potential of distinct IpLITR-types that bound both SHP-1 and SHP-2 following the phosphorylation of tyrosine residues within their cytoplasmic tail (CYT) regions. Phosphatase recruitment by IpLITRs represents an important first step in understanding their influence on immune cell effector functions and suggests that certain inhibitory signaling pathways are conserved among vertebrates.
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Benjamin C S
authors.initials: BC
authors.lastname: Montgomery
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Mewes
authors.forename: Chelsea
authors.initials: C
authors.lastname: Davidson
authors.forename: Deborah N
authors.initials: DN
authors.lastname: Burshtyn
authors.forename: James L
authors.initials: JL
authors.lastname: Stafford
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000276:immunology* / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007059:Ictaluridae / Q000235:genetics / Q000276:immunology*; D007962:Leukocytes / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000235:genetics / Q000378:metabolism*; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000235:genetics / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D016415:Sequence Alignment; D014162:Transfection; D015027:Zebrafish / Q000196:embryology / Q000235:genetics; D018909:src Homology Domains / Q000276:immunology
chemical_list: D011971:Receptors, Immunologic; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6