Enhancement of hepatocyte growth factor-induced cell scattering in N-acetylglucosaminyltransferase III-transfected HepG2 cells.
N-Acetylglucosaminyltransferase III (GnT-III), which catalyzes the synthesis of a bisecting GlcNAc residue of N-glycans, is thought to be involved in the function of glycoproteins such as growth factor receptors. We investigated the effects of the overexpression of GnT-III on the hepatocyte growth factor (HGF) receptor c-Met, a glycoprotein, in human hepatocarcinoma HepG2 cells. GnT-III activity was elevated about 250-fold in HepG2 cells stably transfected with the GnT-III gene, whereas no significant change in GnT-III activity was observed in mock transfectants. Cell scattering assay revealed that HGF-induced cell scattering was enhanced depending on the GnT-III activities in the GnT-III transfectants. Western blot analysis and E-PHA lectin blot analysis showed that the level of c-Met protein was the same in both transfectants; however, the bisecting GlcNAc residue on c-Met was detected only in the GnT-III transfectants. Although the peak level of c-Met phosphorylation was not different in both transfectants, the level of tyrosine phosphorylation of c-Met decreased more rapidly in the GnT-III transfectants than in the mock transfectants. Furthermore, HGF-induced extracellular-regulated kinase (ERK) phosphorylation was slightly higher in the GnT-III transfectants than in the mock transfectants. These results show that overexpression of GnT-III in HepG2 cells enhances HGF-induced cell scattering, which may result from, at least in part, enhancement of HGF-induced ERK phosphorylation.
Hyuga
Masashi
M
Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, Tokyo, Japan. mhyuga@nihs.go.jp
Hyuga
Sumiko
S
Kawasaki
Nana
N
Ohta
Miyako
M
Itoh
Satsuki
S
Niimi
Shingo
S
Kawanishi
Toru
T
Hayakawa
Takao
T
D045744:Cell Line, Tumor; D017228:Hepatocyte Growth Factor / Q000378:metabolism*; D006801:Humans; D017351:N-Acetylglucosaminyltransferases / Q000096:biosynthesis* / Q000235:genetics; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism*; D012542:Scattering, Radiation; D014162:Transfection / Q000379:methods*
D017228:Hepatocyte Growth Factor; D017351:N-Acetylglucosaminyltransferases; C054599:beta-1,4-mannosyl-glycoprotein beta-1,4-N-acetylglucosaminyltransferase; D019859:Proto-Oncogene Proteins c-met