DRIM modulates Src activation and regulates angiogenic functions in vascular endothelial cells

Area of Science:

• Molecular Biology
• Cell Biology
• Oncology

Background:

• Downregulated in Metastasis Protein (DRIM) was initially identified in malignant epithelial cells, primarily considered a nuclear protein.
• Recent single-cell sequencing revealed DRIM's abundant expression in vascular endothelial cells, with its role in endothelium unknown.
• Understanding DRIM's function in endothelial cells is crucial for insights into vascular biology and disease.

Purpose of the Study:

• To investigate the localization and function of DRIM in human vascular endothelial cells.
• To elucidate the molecular mechanisms underlying DRIM's role in endothelial cells.
• To identify potential interactions and downstream effects of DRIM in the endothelium.

Main Methods:

• Protein fractionation and cell imaging to determine DRIM localization.
• DRIM knockdown in endothelial cells to assess functional impacts.
• Proteomics analysis and protein interaction assays to identify DRIM's molecular targets.
• Western blotting to analyze phosphorylation states of key signaling proteins (Src, FAK, STAT3).

Main Results:

• DRIM was localized to both the nucleus and cytoskeletal fractions of human vascular endothelial cells.
• DRIM knockdown significantly impaired endothelial cell growth, migration, and angiogenic tubule formation.
• Src kinase was identified as a direct target of DRIM; DRIM silencing increased Src phosphorylation at Tyr419.
• Downstream signaling proteins, including p-FAK and p-STAT3, were affected by DRIM manipulation via Src.

Conclusions:

• DRIM functions as both a nuclear and cytoskeletal protein in vascular endothelial cells.
• DRIM plays a critical, previously unrecognized role in regulating endothelial cell behavior and angiogenesis.
• DRIM influences endothelial function through the Src signaling pathway.