title: Association of ligand-receptor complexes with actin filaments in human neutrophils: a possible regulatory role for a G-protein.
abstract: Most ligand-receptor interactions result in an immediate generation of various second messengers and a subsequent association of the ligand-receptor complex to the cytoskeleton. Depending on the receptor involved, this linkage to the cytoskeleton has been suggested to play a role in the termination of second messenger generation and/or the endocytic process whereby the ligand-receptor complex is internalized. We have studied how the binding of chemotactic peptide-receptor complexes to the cytoskeleton of human neutrophils is accomplished. As much as 76% of the tritiated formylmethionyl-leucyl-phenylalanine (fMet-Leu-[3H]Phe) specifically bound to intact cells, obtained by a 30-s stimulation with 20 nM fMet-Leu-[3H]Phe, still remained after Triton X-100 extraction. Preincubating intact cells with dihydrocytochalasin B (dhCB) or washing the cytoskeletal preparation with a high concentration of potassium, reduced the binding of ligand-receptor complexes to the cytoskeleton by 46% or more. Inhibition of fMet-Leu-Phe-induced generation of second messengers by ADP-ribosylating the alpha-subunit of the receptor-coupled G-protein with pertussis toxin, did not reduce the binding of ligand-receptor complexes to the cytoskeleton. However, using guanosine-5'-O-(2-thiodiphosphate) (GDP beta S) to prevent the dissociation of the fMet-Leu-Phe-associated G-protein within electrically permeabilized cells, led to a pronounced reduction (62%) of the binding between ligand-receptor complexes and the cytoskeleton. In summary, in human neutrophils the rapid association between chemotactic peptide-receptor complexes and the cytoskeleton is dependent on filamentous actin. This association is most likely regulated by the activation and dissociation of the fMet-Leu-Phe-associated G-protein.
authors.affiliation: Department of Medical Microbiology, University of Linköping, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Särndahl
authors.forename: M
authors.initials: M
authors.lastname: Lindroth
authors.forename: T
authors.initials: T
authors.lastname: Bengtsson
authors.forename: M
authors.initials: M
authors.lastname: Fällman
authors.forename: J
authors.initials: J
authors.lastname: Gustavsson
authors.forename: O
authors.initials: O
authors.lastname: Stendahl
authors.forename: T
authors.initials: T
authors.lastname: Andersson
mesh_terms: D000199:Actins / Q000097:blood*; D000911:Antibodies, Monoclonal; D003571:Cytochalasin B / Q000031:analogs & derivatives / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D019204:GTP-Binding Proteins / Q000097:blood* / Q000502:physiology; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008024:Ligands; D008855:Microscopy, Electron, Scanning; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism*; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism*; D037342:Pertussis Toxin; D011189:Potassium Chloride / Q000494:pharmacology; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000187:drug effects / Q000378:metabolism*; D013873:Thionucleotides / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D000199:Actins; D000911:Antibodies, Monoclonal; D008024:Ligands; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D006153:Guanosine Diphosphate; C024794:dihydrocytochalasin B; D003571:Cytochalasin B; D009240:N-Formylmethionine Leucyl-Phenylalanine; D011189:Potassium Chloride; C023427:guanosine 5'-O-(2-thiodiphosphate); D037342:Pertussis Toxin; D019204:GTP-Binding Proteins