Ndm, a coiled-coil domain protein that suppresses macropinocytosis and has effects on cell migration.
The ampA gene has a role in cell migration in Dictyostelium discoideum. Cells overexpressing AmpA show an increase in cell migration, forming large plaques on bacterial lawns. A second-site suppressor of this ampA-overexpressing phenotype identified a previously uncharacterized gene, ndm, which is described here. The Ndm protein is predicted to contain a coiled-coil BAR-like domain-a domain involved in endocytosis and membrane bending. ndm-knockout and Ndm-monomeric red fluorescent protein-expressing cell lines were used to establish a role for ndm in suppressing endocytosis. An increase in the rate of endocytosis and in the number of endosomes was detected in ndm(-) cells. During migration ndm(-) cells formed numerous endocytic cups instead of the broad lamellipodia structure characteristic of moving cells. A second lamellipodia-based function-cell spreading-was also defective in the ndm(-) cells. The increase in endocytosis and the defect in lamellipodia formation were associated with reduced chemotaxis in ndm(-) cells. Immunofluorescence results and glutathione S-transferase pull-down assays revealed an association of Ndm with coronin and F-actin. The results establish ndm as a gene important in regulating the balance between formation of endocytic cups and lamellipodia structures.
Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
Jessica S
JS
Kelsey
Nathan M
NM
Fastman
Elizabeth F
EF
Noratel
Daphne D
DD
Blumberg
D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D008841:Actin Cytoskeleton / Q000648:ultrastructure; D000199:Actins / Q000378:metabolism; D002460:Cell Line; D002465:Cell Movement; D004023:Dictyostelium / Q000235:genetics / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D055786:Gene Knockout Techniques; D008666:Metalloendopeptidases / Q000235:genetics / Q000378:metabolism; D010873:Pinocytosis; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011554:Pseudopodia / Q000378:metabolism / Q000648:ultrastructure; D054378:Acetogenins
D015107:4-Butyrolactone; D000199:Actins; D008666:Metalloendopeptidases; D015800:Protozoan Proteins; C438920:coronin acetogenin; D054378:Acetogenins; C478220:AmpA protein, Dictyostelium protozoan