Evidence for phosphorylation of rat liver glucose-regulated protein 58, GRP58/ERp57/ER-60, induced by fasting and leptin.
Glucose-regulated protein 58 (GRP58)-like immunoreactivity in rat liver obtained in the evening or after fasting underwent an electrophoretic band-shift, which disappeared after phosphatase-treatment. Since mass spectrometric analysis raised a possibility that Ser150 of GRP58 is phosphorylated, an antibody against the phosphoserine150 GRP58 was generated. Immunoreactivity to this antibody was increased in the evening and after fasting. Since GRP58 was shown to interact with signal transducer and activator of transduction 3 (STAT3), a leptin-related protein, the effect of leptin was examined. Immunoreactivity to the anti-phosphoGRP58 antibody was markedly elevated after the leptin injection, indicating that Ser150 of GRP58 is phosphorylated after fasting and leptin-treatment.
Kita
Kanako
K
Laboratory of Proteins Involved in Homeostatic Integration, Institute for Protein Research, Osaka University, 3-2, Yamada-Oka, Suita, Osaka 565-0871, Japan.
Okumura
Nobuaki
N
Takao
Toshifumi
T
Watanabe
Makoto
M
Matsubara
Toshiya
T
Nishimura
Osamu
O
Nagai
Katsuya
K
D000818:Animals; D015180:Electrophoresis, Gel, Two-Dimensional; D005215:Fasting / Q000378:metabolism*; D005508:Food Deprivation / Q000502:physiology; D006360:Heat-Shock Proteins / Q000378:metabolism*; D020738:Leptin / Q000008:administration & dosage* / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D013058:Mass Spectrometry; D010766:Phosphorylation / Q000187:drug effects; D019704:Protein Disulfide-Isomerases / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D050796:STAT3 Transcription Factor / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
D006360:Heat-Shock Proteins; D020738:Leptin; D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat; D012694:Serine; C513196:PDIA3 protein, rat; D019704:Protein Disulfide-Isomerases