Effects of Cot expression on the nuclear translocation of NF-kappaB in RBL-2H3 cells.
Cot is a serine/threonine protein kinase and is classified as a mitogen-activated protein (MAP) kinase kinase kinase. Overexpression of this protein has been shown to activate the extracellular signal-regulated kinase, the c-Jun N-terminal kinase, and the p38 MAP kinase pathways and to stimulate NF-AT and NF-kappaB-dependent transcription. Here we have shown that Cot kinase activity is intimately involved in the high affinity receptor for IgE (FcvarepsilonRI)-mediated nuclear translocation of NF-kappaB1 independent of NF-kappaB-inducing kinase (NIK) in rat basophilic leukemia (RBL-2H3) cells. A transfected green fluorescent protein-tagged NF-kappaB1 (GFP-NF-kappaB1) resided in the cytoplasm in RBL-2H3 cells and it remained in the cytoplasm even when Cot tagged with red fluorescent protein (Cot-RFP) was co-expressed. Western blotting analysis showed that IkappaB kinases (IKKs) were expressed in RBL-2H3 cells but NIK was not. GFP-NF-kappaB1 translocated from the cytoplasm to the nucleus after the aggregation of FcvarepsilonRI in Cot-transfected cells but not in kinase-deficient Cot-transfected cells. This finding gives a new insight into the role of Cot in the FcvarepsilonRI-mediated NF-kappaB activation in mast cells.
Chikamatsu
Satomi
S
Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan.
Furuno
Tadahide
T
Kinoshita
Yosuke
Y
Inoh
Yoshikazu
Y
Hirashima
Naohide
N
Teshima
Reiko
R
Nakanishi
Mamoru
M
D021581:Active Transport, Cell Nucleus; D000818:Animals; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism*; D003593:Cytoplasm / Q000737:chemistry / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000032:analysis; D008164:Luminescent Proteins / Q000032:analysis; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D008407:Mast Cells / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000032:analysis / Q000378:metabolism*; D041681:NIH 3T3 Cells; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017455:Receptors, IgE / Q000378:metabolism*; D000097573:Red Fluorescent Protein
D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D020930:MAP Kinase Kinase Kinases; D016328:NF-kappa B; D011518:Proto-Oncogene Proteins; D017455:Receptors, IgE; D000097573:Red Fluorescent Protein; C080356:Map3k8 protein, rat