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The retinoblastoma susceptibility gene product/Sp1 signalling pathway is modulated by Ca2+/calmodulin kinases II and

F Sohm1, C Gaiddon, M Antoine

  • 1IPCB, UMR 7519 CNRS, Strasbourg, France.

Oncogene
|May 29, 1999
PubMed

Insights

Calcium/calmodulin-dependent kinases (CamK) II and IV link Ca2+ signaling to cell cycle control. They regulate c-fos transcription via the retinoblastoma/SP1 pathway, impacting cell cycle progression.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Calcium (Ca2+) signaling plays a crucial role in cellular processes.
  • Cell cycle control is essential for cell proliferation and development.
  • The retinoblastoma (Rb) susceptibility gene product and SP1 are key regulators of gene expression and cell cycle.

Purpose of the Study:

  • To investigate the interaction between Ca2+ signaling and cell cycle control.
  • To elucidate the role of Ca2+/calmodulin-dependent kinases (CamK) in regulating gene expression related to cell cycle progression.
  • To determine the involvement of the retinoblastoma (Rb)/SP1 pathway in CamK-mediated transcriptional regulation.

Main Methods:

  • Analysis of Ca2+/calmodulin kinases (CamK) interaction with the retinoblastoma susceptibility gene product/SP1 pathway.
  • Deletion analysis of the c-fos promoter region.
  • Gel shift experiments to confirm protein-DNA interactions.
  • Transient transfection experiments using Gal4/SP1 fusion proteins.

Main Results:

  • CamK II and IV activate c-fos transcription through a promoter region containing retinoblastoma control element (RCE) and cAMP response element (CRE) sequences.
  • The RCE is a major CamK-responsive element sufficient for Ca2+ regulation.
  • CamK-dependent transcription is regulated by Rb and p107 proteins, with effects mediated by SP1.
  • Overexpression of Rb and p107 proteins blocks the stimulatory effects of CamKs and Rb on c-fos.

Conclusions:

  • CamK II and IV act as molecular links between Ca2+ transduction and cell cycle control effectors.
  • The Rb/SP1 signaling pathway is a key mediator of CamK-regulated gene expression impacting cell cycle progression.
  • Ca2+ signaling influences cell cycle control through the modulation of Rb/SP1 pathway activity.

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