Sign up for Table of Contents Alerts.

Email this page

Print this page

Brief Report

Redundant Ubiquitin Ligase Activities Regulate Wee1 Degradation and Mitotic Entry

Anthony Smith, Scott Simanski, Mohammad Fallahi and Nagi G. Ayad

Purchase article for $19

Subscribe to this journal for $129/year

The irreversible nature of mitotic entry is due to the activation of mitosis specific kinases such as cdk1/cyclin B. Cdk1/cyclin B induces activation of mitosis by promoting phosphatases while suppressing inhibitory factors such as the tyrosine kinase wee1. Since wee1 keeps cdk1/cyclin B inactive during the S and G₂ phases, its activity must be down-regulated for mitotic progression to occur. One mechanism of suppressing wee1 activity is ubiquitin-dependent proteolysis. Cdk1/cyclin B1 phosphorylates wee1, targeting it for recognition by ubiquitin ligases and subsequent proteasomal degradation. One of the ubiquitin ligases promoting wee1 destruction during mitosis is the SCFβ-trcp complex. We demonstrate that this complex, and a second SCF complex containing the F-box protein Tome-1, regulate wee1 degradation during the S and G₂ phases of the cell cycle. Therefore, redundant ubiquitin ligase activities promote efficient mitotic entry of eukaryotic cells.

Authors

Anthony Smith

The Scripps Research Institute; Jupiter, FL

Scott Simanski

The Scripps Research Institute; Jupiter, FL

Mohammad Fallahi

The Scripps Research Institute; Jupiter, FL

Nagi G. Ayad

The Scripps Research Institute; Jupiter, FL

Purchase article for $19

Subscribe to this journal for $129/year