Cross-linking of SIGNR1 activates JNK and induces TNF-alpha production in RAW264.7 cells that express SIGNR1.
In this study, we evaluated the signaling ability of SIGNR1 in murine macrophage-like RAW264.7 cells that stably expressed FLAG-tagged SIGNR1 (SIGNR1-FLAG). Cross-linking of SIGNR1-FLAG expressed on the cells by an anti-FLAG antibody induced JNK phosphorylation without induction of phosphorylation of ERK1/2 and p38 MAP kinase, and led to phosphorylations of Src family kinases (SFKs) and Akt. The SIGNR1-FLAG molecules in the cells were found in lipid raft-enriched membrane fractions, and the tyrosine kinases Lyn, Hck, and Fgr co-precipitated with SIGNR1-FLAG in the lipid raft fractions. The antibody-induced JNK phosphorylation was inhibited by inhibitors of SFKs and tyrosine kinases. Furthermore, cross-linking of SIGNR1 led to production of TNF-alpha, and the JNK inhibitor inhibited the antibody-induced TNF-alpha production. These results show that cross-linking of SIGNR1 triggers phosphorylation of SFKs, which leads to activation of the JNK pathway and induction of TNF-alpha production in macrophage-like RAW264.7 cells.
Numazaki
Maki
M
Department of Applied Biochemistry, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan.
Kato
Chiaki
C
Kawauchi
Yoko
Y
Kajiwara
Toshimitsu
T
Ishii
Mariko
M
Kojima
Naoya
N
D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002460:Cell Line; D037181:Lectins, C-Type / Q000378:metabolism*; D048670:MAP Kinase Kinase 4 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D021962:Membrane Microdomains / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*; D019061:src-Family Kinases / Q000378:metabolism; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
D015815:Cell Adhesion Molecules; D037181:Lectins, C-Type; D048670:MAP Kinase Kinase 4; D047428:Protein Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D011956:Receptors, Cell Surface; D014409:Tumor Necrosis Factor-alpha; D019061:src-Family Kinases; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin