title: Requirements for leukocyte transmigration via the transmembrane chemokine CX3CL1.
abstract: The surface-expressed transmembrane CX3C chemokine ligand 1 (CX3CL1/fractalkine) induces firm adhesion of leukocytes expressing its receptor CX3CR1. After shedding by the disintegrins and metalloproteinases (ADAM) 10 and 17, CX3CL1 also acts as soluble leukocyte chemoattractant. Here, we demonstrate that transmembrane CX3CL1 expressed on both endothelial and epithelial cells induces leukocyte transmigration. To investigate the underlying mechanism, we generated CX3CR1 variants lacking the intracellular aspartate-arginine-tyrosine (DRY) motif or the intracellular C-terminus which led to a defect in intracellular calcium response and impaired ligand uptake, respectively. While both variants effectively mediated firm cell adhesion, they failed to induce transmigration and rather mediated retention of leukocytes on the CX3CL1-expressing cell layer. Targeting of ADAM10 led to increased adhesion but reduced transmigration in response to transmembrane CX3CL1, while transmigration towards soluble CX3CL1 was not affected. Thus, transmembrane CX3CL1 mediates leukocyte transmigration via the DRY motif and C-terminus of CX3CR1 and the activity of ADAM10.
authors.affiliation: Institute of Pharmacology and Toxicology, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Schwarz
authors.forename: Jessica
authors.initials: J
authors.lastname: Pruessmeyer
authors.forename: Franz M
authors.initials: FM
authors.lastname: Hess
authors.forename: Daniela
authors.initials: D
authors.lastname: Dreymueller
authors.forename: Elena
authors.initials: E
authors.lastname: Pantaler
authors.forename: Anne
authors.initials: A
authors.lastname: Koelsch
authors.forename: Reinhard
authors.initials: R
authors.lastname: Windoffer
authors.forename: Matthias
authors.initials: M
authors.lastname: Voss
authors.forename: Alisina
authors.initials: A
authors.lastname: Sarabi
authors.forename: Christian
authors.initials: C
authors.lastname: Weber
authors.forename: Antonio S
authors.initials: AS
authors.lastname: Sechi
authors.forename: Stefan
authors.initials: S
authors.lastname: Uhlig
authors.forename: Andreas
authors.initials: A
authors.lastname: Ludwig
mesh_terms: D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism; D000072197:ADAM10 Protein; D000072198:ADAM17 Protein; D000595:Amino Acid Sequence; D053829:Amyloid Precursor Protein Secretases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000073883:CX3C Chemokine Receptor 1; D020013:Calcium Signaling / Q000502:physiology; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D054428:Chemokine CX3CL1 / Q000235:genetics / Q000378:metabolism*; D002633:Chemotaxis / Q000502:physiology; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology; D006801:Humans; D007962:Leukocytes / Q000166:cytology / Q000502:physiology*; D008024:Ligands; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D019707:Receptors, Chemokine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D057705:Transendothelial and Transepithelial Migration / Q000502:physiology*
chemical_list: D000073883:CX3C Chemokine Receptor 1; C515538:CX3CL1 protein, human; C095235:CX3CR1 protein, human; D054428:Chemokine CX3CL1; D008024:Ligands; D008565:Membrane Proteins; D019707:Receptors, Chemokine; D053829:Amyloid Precursor Protein Secretases; D051722:ADAM Proteins; D000072197:ADAM10 Protein; C491236:ADAM10 protein, human; D000072198:ADAM17 Protein