Related Experiment Video

Updated: Jul 25, 2026

Xenopus laevis as a Model to Identify Translation Impairment
10:24

Xenopus laevis as a Model to Identify Translation Impairment

Published on: September 27, 2015

The pathway of MAP kinase mediation of CSF arrest in Xenopus oocytes

J L Maller1, M S Schwab, B T Roberts

  • 1Howard Hughes Medical Institute and Department of Pharmacology, University of Colorado School of Medicine, Denver 80262, USA. Jim.Maller@uchsc.edu

Biology of the Cell
|December 4, 2001
PubMed

Insights

Cytostatic factor (CSF) activity in oocytes, crucial for metaphase arrest, is initiated by Mos and the MAPK pathway. This process involves p90Rsk protein kinase, linking MAPK signaling to the spindle assembly checkpoint.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Developmental Biology

Background:

  • A cytoplasmic activity, known as cytostatic factor (CSF), causes metaphase arrest in mature oocytes.
  • This arrest is essential for proper meiotic progression and has been studied for over 30 years in amphibians.

Purpose of the Study:

  • To elucidate the molecular mechanisms underlying CSF-mediated metaphase arrest in Xenopus oocytes.
  • To identify the key signaling pathways and protein interactions involved in maintaining meiotic arrest.

Main Methods:

  • Investigated the role of the Mos-MAPK pathway in initiating CSF activity.
  • Examined the function of p90Rsk, a MAPK target, in regulating cyclin B degradation.
  • Assessed the phosphorylation and activation of Bub1 protein kinase by p90Rsk.

Main Results:

  • Progesterone induces Mos synthesis, activating the MAPK pathway, which is upstream of CSF activity.
  • p90Rsk directly inhibits cyclin B degradation by the anaphase-promoting complex (APC).
  • p90Rsk phosphorylates and activates Bub1, a key component of the spindle assembly checkpoint.

Conclusions:

  • CSF arrest in Xenopus oocytes is mediated by p90Rsk, a downstream target of the MAPK pathway.
  • p90Rsk links MAPK signaling to the APC, preventing premature anaphase.
  • This study reveals a conserved mechanism connecting the MAPK pathway and the spindle assembly checkpoint in cell cycle regulation.

More Related Videos

Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development09:32

Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development

Published on: June 15, 2017

Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes10:09

Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes

Published on: September 13, 2022

Related Concept Videos

Microtubule Associated Proteins (MAPs)01:42

Microtubule Associated Proteins (MAPs)

Microtubule function and architecture are regulated by an array of specialized proteins called microtubule-associated proteins or MAPs. These proteins are widespread across different organisms and have conserved protein motifs, like the multi-TOG domain for tubulin binding found in the CLASP family of MAPs. Some MAPs are lineage-specific based on their conserved domains. Their functions depend upon the cytoskeletal architecture and cell type they are located within. In-plant cells, a specific...
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...