title: Chemoattractant induces LFA-1 associated PI 3K activity and cell migration that are dependent on Fyn signaling.
abstract: The activation state of integrins on leukocytes is tightly controlled by the association of intracellular molecules to the cytoplasmic domain of the integrin. To identify signaling intermediates involved in chemoattractant receptor-induced integrin activation, we analyzed the ability of LFA-1 integrin to associate with members of Src tyrosine kinase and phosphatidylinositol 3Kinase (PI 3K) families following fMLP stimulation of a lymphoid T cell line stably expressing the fMLP receptor (fPR). fMLP-induced cell activation resulted in a rapid increase of integrin-associated PI 3Kinase activity in G protein and Src kinase dependent manner. We show, upon fMLP-stimulation, a rapid and transient association of the Src tyrosine kinase Fyn with LFA-1. Also, by transiently expressing mutant forms of this kinase, we demonstrated that Fyn is required for the integrin associated PI 3K activity. Furthermore, overexpression of the mutant form of Fyn resulted in a significant impairment of fMLP-induced cell migration through ICAM-1-coated filters, while ICAM-1 independent migration was not affected. Our observations indicate that chemoattractant receptor engagement induces Fyn-dependent PI 3K activation in association with LFA-1 and suggests that Fyn is necessary to initiate and/or to regulate chemoattractant-mediated LFA-1 activation to promote directional migration.
authors.affiliation: Department of Experimental Medicine and Pathology University, La Sapienza, Rome, Italy. giovanni.bernardini@uniroma1.it
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bernardini
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Kim
authors.forename: Angela
authors.initials: A
authors.lastname: Gismondi
authors.forename: Eugene C
authors.initials: EC
authors.lastname: Butcher
authors.forename: Angela
authors.initials: A
authors.lastname: Santoni
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000494:pharmacology; D002630:Chemotactic Factors / Q000494:pharmacology*; D004790:Enzyme Induction; D016169:Lymphocyte Function-Associated Antigen-1 / Q000502:physiology*; D051379:Mice; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D037342:Pertussis Toxin / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000096:biosynthesis*; D051076:Proto-Oncogene Proteins c-fyn / Q000502:physiology*; D044042:Receptors, Formyl Peptide / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D019061:src-Family Kinases / Q000502:physiology*
chemical_list: D054377:Chemokine CXCL12; D019743:Chemokines, CXC; D002630:Chemotactic Factors; C515256:Cxcl12 protein, mouse; D016169:Lymphocyte Function-Associated Antigen-1; D044042:Receptors, Formyl Peptide; D009240:N-Formylmethionine Leucyl-Phenylalanine; D037342:Pertussis Toxin; D019869:Phosphatidylinositol 3-Kinases; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn; D019061:src-Family Kinases