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.
Chemotaxis Signal Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Twinbrook II Facility, 12331 Parklawn Drive, Rockville, MD 20852, USA.
Nilgun
N
Isik
Joseph A
JA
Brzostowski
Tian
T
Jin
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