The 100-kDa proteolytic fragment of RB is retained predominantly within the nuclear compartment of apoptotic cells.

Journal Article (Journal Article)

The retinoblastoma tumor suppressor protein (RB) has been shown to play a role in regulating the eukaryotic cell cycle, promoting cellular differentiation, and modulating programmed cell death. Although regulation of RB tumor suppressor activity is mediated by reversible phosphorylation, an additional posttranslational modification involves the cleavage of 42 residues from the carboxy terminus of RB during the onset of drug-induced or receptor-mediated apoptosis. We now demonstrate that a recombinant p100cl RB species localizes to the nucleus where it may retain wildtype "pocket" protein binding activity. In addition, using immunocytochemistry, we show that cleavage of the endogenous RB protein occurs in vivo in human cells and that p100cl is predominantly retained within the nuclear compartment of cells during early apoptosis. We also show that the carboxy-terminal cleavage of RB is detected immediately following caspase-3 and PARP cleavage during FAS-mediated apoptosis of MCF10 cells. These findings suggest that this cleavage event may be a component of a downstream cascade during programmed cell death.

Full Text

Duke Authors

Cited Authors

  • Chen, WD; Geradts, J; Keane, MM; Lipkowitz, S; Zajac-Kaye, M; Kaye, FJ

Published Date

  • June 1999

Published In

Volume / Issue

  • 1 / 3

Start / End Page

  • 216 - 220

PubMed ID

  • 10425229

International Standard Serial Number (ISSN)

  • 1522-4724

Digital Object Identifier (DOI)

  • 10.1006/mcbr.1999.0132


  • eng

Conference Location

  • United States