Requirements for leukocyte transmigration via the transmembrane chemokine CX3CL1.
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.
Schwarz
Nicole
N
Institute of Pharmacology and Toxicology, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.
Pruessmeyer
Jessica
J
Hess
Franz M
FM
Dreymueller
Daniela
D
Pantaler
Elena
E
Koelsch
Anne
A
Windoffer
Reinhard
R
Voss
Matthias
M
Sarabi
Alisina
A
Weber
Christian
C
Sechi
Antonio S
AS
Uhlig
Stefan
S
Ludwig
Andreas
A
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*
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