Identification of p46 Shc expressed in the nuclei of hepatocytes with high proliferating activity: Study of regenerating rat liver.
The adaptor molecule Shc is a proto-oncogene product, and it is known to be associated with cell proliferation. However, the role of Shc in the proliferation and regeneration of hepatocytes remains unknown. In the present study, we report that p46 Shc is specifically expressed in the nuclei of proliferative (or regenerative) hepatocytes, suggesting that p46 Shc protein plays a role in hepatocellular proliferation. The expression of Shc was analyzed in liver tissue after partial hepatectomy (PH) or sham operation in Wistar rats by using immunohistochemistry and/or Western blot analysis. In addition, the expression of various cell cycle-related proteins, such as Cdk4, cyclin D1, PCNA, and Cdk1 was analyzed in the tissues of regenerating rat liver. Furthermore, the tyrosine phosphorylation of Shc was studied in liver tissue after PH or sham operation by immunoprecipitation using a monoclonal phosphotyrosine antibody. Although the protein levels of p52 Shc were unchanged in liver tissues after PH or sham operation, tyrosine phosphorylation was detected only in the regenerating rat liver after PH. The levels of p46 Shc protein were markedly increased in liver tissues during the liver regenerative process. In contrast, p66 Shc was not detected in the liver tissues after PH or sham operation. Western blotting and immunohistochemistry showed that the main location of p46 Shc was in the nuclei of proliferating hepatocytes after PH. These data suggest that p46 Shc expressed in hepatocellular nuclei may be closely related to the proliferation of hepatocytes. Therefore, it is suggested that p46 Shc expressed in hepatocellular nuclei may be a useful marker for detecting hepatocytes with high proliferative activity.
Yuji
Jin
J
Third Department of Internal Medicine, Kagawa University School of Medicine, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Masaki
Tsutomu
T
Yoshida
Shuhei
S
Kita
Yuko
Y
Feng
Han
H
Uchida
Naohito
N
Yoshiji
Hitoshi
H
Kitanaka
Akira
A
Watanabe
Seishiro
S
Kurokohchi
Kazutaka
K
Kuriyama
Shigeki
S
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002455:Cell Division; D002458:Cell Fractionation; D002467:Cell Nucleus / Q000378:metabolism*; D019938:Cyclin D1 / Q000378:metabolism; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D006498:Hepatectomy; D022781:Hepatocytes / Q000166:cytology* / Q000378:metabolism*; D007150:Immunohistochemistry; D008115:Liver Regeneration / Q000502:physiology*; D010766:Phosphorylation; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D018809:Proliferating Cell Nuclear Antigen; D011518:Proto-Oncogene Proteins; D055765:Shc Signaling Adaptor Proteins; C528035:Shc1 protein, rat; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D019938:Cyclin D1; D014443:Tyrosine; D016203:CDC2 Protein Kinase; C495903:Cdk4 protein, rat; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases