Ndm, a coiled-coil domain protein that suppresses macropinocytosis and has effects on cell migration

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• The ampA gene influences cell migration in Dictyostelium discoideum, with overexpression enhancing this process.
• A suppressor screen for ampA overexpression identified a novel gene, ndm, crucial for cellular functions.

Purpose of the Study:

• To characterize the function of the newly identified ndm gene in Dictyostelium discoideum.
• To investigate the role of Ndm protein in regulating cell migration, endocytosis, and cytoskeletal dynamics.

Main Methods:

• Gene knockout and expression studies using ndm-knockout and Ndm-monomeric red fluorescent protein cell lines.
• Analysis of endocytosis rates, endosome formation, and cell morphology during migration.
• Biochemical assays including immunofluorescence and glutathione S-transferase pull-down to determine protein interactions.

Main Results:

• Ndm protein, predicted to have a BAR-like domain, suppresses endocytosis.
• ndm knockout cells exhibit increased endocytosis, more endosomes, and defective lamellipodia formation and cell spreading.
• Defects in ndm(-) cells correlate with reduced chemotaxis and altered cell migration dynamics.
• Ndm associates with coronin and F-actin, suggesting a role in cytoskeletal regulation.

Conclusions:

• The ndm gene is essential for regulating the balance between endocytic cup and lamellipodia formation during cell migration.
• Ndm plays a critical role in controlling endocytosis and maintaining proper cell morphology and movement in Dictyostelium discoideum.