An Elmo-like protein associated with myosin II restricts spurious F-actin events to coordinate phagocytosis and chemotaxis.
Elmo proteins positively regulate actin polymerization during cell migration and phagocytosis through activation of the small G protein Rac. We identified an Elmo-like protein, ElmoA, in Dictyostelium discoideum that unexpectedly functions as a negative regulator of actin polymerization. Cells lacking ElmoA display an elevated rate of phagocytosis, increased pseudopod formation, and excessive F-actin localization within pseudopods. ElmoA associates with cortical actin and myosin II. TIRF microscopic observations of functional ElmoA-GFP reveal that a fraction of ElmoA localizes near the presumptive actin/myosin II cortex and the levels of ElmoA and myosin II negatively correlate with that of polymerizing F-actin. F-actin-regulated dynamic dispersions of ElmoA and myosin II are interdependent. Taken together, our data suggest that ElmoA modulates actin/myosin II at the cortex to prevent excessive F-actin polymerization around the cell periphery, thereby maintaining proper cell shape during phagocytosis and chemotaxis.
Isik
Nilgun
N
Chemotaxis Signal Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Twinbrook II Facility, 12331 Parklawn Drive, Rockville, MD 20852, USA.
Brzostowski
Joseph A
JA
Jin
Tian
T
D000199:Actins / Q000378:metabolism*; D000818:Animals; D016764:Cell Polarity; D048430:Cell Shape; D002633:Chemotaxis / Q000502:physiology*; D004023:Dictyostelium / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D024462:Myosin Type II / Q000378:metabolism*; D010587:Phagocytosis / Q000502:physiology*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
D000199:Actins; D008840:Microfilament Proteins; D015800:Protozoan Proteins; D049452:Green Fluorescent Proteins; D024462:Myosin Type II; D020744:rac GTP-Binding Proteins