DENND2B activates Rab13 at the leading edge of migrating cells and promotes metastatic behavior

Area of Science:

• Cell Biology
• Molecular Biology
• Cancer Research

Background:

• The small GTPase Rab13 regulates exocytic vesicle trafficking in epithelial cells.
• Dysregulated Rab13 activity is implicated in human cancers, but its activation mechanisms and role in cancer progression are not fully understood.

Purpose of the Study:

• To identify the guanine nucleotide exchange factor (GEF) for Rab13.
• To elucidate the role of Rab13 and its GEF in epithelial cell invasion and cancer progression.

Main Methods:

• Identification of DENND2B as Rab13 GEF.
• Development of a Förster resonance energy transfer (FRET)-based Rab biosensor for real-time Rab13 activation monitoring.
• In vitro and in vivo assays to assess the impact of Rab13 pathway disruption on cell invasion and cancer growth.

Main Results:

• DENND2B was identified as the specific GEF for Rab13.
• Rab13 activation by DENND2B occurs at the leading edge of migrating cells.
• DENND2B interacts with MICAL-L2, facilitating leading edge remodeling.
• Inhibition of Rab13-mediated trafficking significantly reduced epithelial cell invasion in vitro and cancer cell growth and migration in vivo.

Conclusions:

• DENND2B is a key activator of Rab13.
• The DENND2B-Rab13 pathway is crucial for epithelial cell invasion and cancer cell motility.
• Targeting DENND2B-mediated Rab13 activation presents a potential therapeutic strategy to inhibit epithelial cancer metastasis.