Cyclin-dependent kinase 1-mediated phosphorylation of SET at serine 7 is essential for its oncogenic activity

Area of Science:

• Cell Biology
• Molecular Oncology
• Cancer Research

Background:

• SE translocation (SET) protein phosphatase 2A (PP2A) inhibitor has oncogenic activity.
• SET's regulation, particularly its role in tumorigenesis, is not well understood.

Purpose of the Study:

• To identify and characterize novel regulatory mechanisms of SET isoform 1.
• To determine the biological significance of SET isoform 1 phosphorylation in tumorigenesis.

Main Methods:

• In vitro and in vivo kinase assays using cyclin-dependent kinase 1 (CDK1).
• Analysis of SET deletion effects on mitosis and cell behavior.
• Assessment of SET phosphorylation's role in cell migration, invasion, anchorage-independent growth, and xenograft tumor formation.

Main Results:

• CDK1 phosphorylates SET isoform 1 at serine 7 during mitosis.
• SET deletion leads to mitotic errors including multipolar spindles and chromosome missegregation.
• Mitotic phosphorylation of SET isoform 1 is essential for promoting cell migration, invasion, anchorage-independent growth, and tumorigenesis.
• SET phosphorylation influences Akt activity.

Conclusions:

• Mitotic phosphorylation of SET isoform 1 by CDK1 is a critical regulatory event.
• This phosphorylation is vital for SET isoform 1's oncogenic functions, impacting cell division and tumor progression.
• Targeting SET phosphorylation may offer a therapeutic strategy for cancers driven by SET isoform 1.