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Schlafen-1 causes a cell cycle arrest by inhibiting induction of cyclin D1

Gareth Brady1, Louise Boggan, Andrew Bowie

  • 1School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland. bradyg1@tcd.ie

The Journal of Biological Chemistry
|June 11, 2005
PubMed

Insights

Schlafen-1 (Slfn-1) protein halts cell cycle progression in fibroblasts by blocking cyclin D1 induction. This mechanism prevents cells from entering the S phase, impacting cell growth and proliferation.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Schlafen-1 (Slfn-1) is known to induce growth arrest in T-lymphocytes.
  • The precise mechanism by which Slfn-1 affects the cell cycle remains unclear.
  • Previous studies indicated Slfn-1 causes cell cycle arrest prior to the G1/S transition in fibroblasts.

Purpose of the Study:

  • To elucidate the mechanism of cell cycle arrest induced by Slfn-1 in fibroblasts.
  • To identify the molecular targets and signaling pathways affected by Slfn-1.
  • To determine how Slfn-1 influences mitogen-stimulated cell cycle progression.

Main Methods:

  • Synchronization of murine fibroblasts.
  • Stimulation with growth factors like PDGF-BB and EGF.
  • Analysis of cyclin D1 induction and cell cycle progression.
  • Overexpression studies of Slfn-1 and cyclin D1.
  • Assessment of MAPK and PDGF signaling pathways.
  • Reporter assays for cyclin D1 promoter activity.

Main Results:

  • Slfn-1 expression prevented fibroblasts from exiting G1 phase upon stimulation with mitogens.
  • Induction of cyclin D1 and downstream cell cycle events were inhibited by Slfn-1.
  • Overexpression of cyclin D1 rescued the growth arrest phenotype.
  • PDGF signaling was blocked due to reduced PDGF receptor expression.
  • EGF-induced MAPK pathway activation was unaffected.
  • Slfn-1 inhibited cyclin D1 promoter activation.

Conclusions:

  • Slfn-1 induces a G1 cell cycle arrest by inhibiting mitogen-stimulated cyclin D1 induction.
  • Cyclin D1 is identified as a key biological target of Slfn-1.
  • Slfn-1 affects cell cycle progression through modulation of specific signaling pathways and receptor expression.

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