Characterization of 57 kDa statin as a true marker for growth arrest in tissue by its disappearance from regenerating liver.

Published

Journal Article

Statin, a 57 kDa nuclear protein, is lost from quiescent fibroblasts in culture when they are induced to enter the cell cycle by feeding with growth factors, or by removal of contact inhibition. In order to investigate changes in statin expression during the transition from a quiescent to a cycling state in situ, we performed 70% partial hepatectomy on rats and analyzed the regenerating liver by immunofluorescence microscopy with antistatin monoclonal antibodies (S44 mAb), and by immunoblotting of liver proteins in cytoplasmic and enriched nuclear/cytoskeletal fractions. Western blot analysis showed that rat hepatocytes in situ contain a nuclear 57 kDa form of statin, as seen in cultured fibroblasts; however additional S44-immunoreactive polypeptides with molecular weights of 53 and 110 kDa are also present in both cytoplasmic and nuclear/cytoskeletal fractions. Immunofluorescence microscopy indicates that the proportion of S44-positive hepatocyte nuclei drops to approximately 60% within 24 hours after hepatectomy, a time period when re-entry of hepatocytes into the cell cycle is first observed. On Western blots of hepatocyte nuclear/cytoskeletal proteins obtained 24 hours after hepatectomy, the 57 kDa form of statin is markedly reduced. These results suggest that, although in liver the S44 antibody recognizes three proteins (53 kDa, 57 kDa, and 110 kDa), the 57 kDa in intact liver, similar to cultured fibroblasts, is the only polypeptide recognized by the statin antibody that disappears when hepatocytes are induced to re-enter the cell cycle from a quiescent state.

Full Text

Duke Authors

Cited Authors

  • Sandig, M; Bissonnette, R; Liu, CH; Tomaszewski, G; Wang, E

Published Date

  • February 1994

Published In

Volume / Issue

  • 158 / 2

Start / End Page

  • 277 - 284

PubMed ID

  • 8106565

Pubmed Central ID

  • 8106565

International Standard Serial Number (ISSN)

  • 0021-9541

Digital Object Identifier (DOI)

  • 10.1002/jcp.1041580210

Language

  • eng

Conference Location

  • United States