RGD-containing molecules induce macropinocytosis in ascidian hyaline amoebocytes.
Phagocytes of the compound ascidian Botryllus schlosseri are capable of constitutive macropinocytosis (MP) at sites of membrane ruffling along the leading edge. This gives rise to the formation of initially irregular vesicles which then move to the inside of the cells and acquire a more regular morphology. Both phagocyte spreading and MP are enhanced by the recognition of molecules containing the sequence Arg-Gly-Asp (RGD): this suggests that, as in mammals, integrin activation is involved in the induction of both cell spreading and endocytosis. The occurrence of MP is associated with increased oxygen consumption and a rise in the production of superoxide anion, as indicated by nitroblue tetrazolium reduction, and ATP, as indicated by increased cytochrome oxidase activity. On the whole, our results indicate the conservation of common mechanisms of MP induction throughout the Chordate phylum.
Ballarin
Loriano
L
Department of Biology, University of Padova, Via U.Bassi 58/B, 35100 Padova, Italy. loriano.ballarian@unipd.it
Burighel
Paolo
P
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D003576:Electron Transport Complex IV / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000378:metabolism; D016023:Integrins / Q000502:physiology; D008854:Microscopy, Electron; D009580:Nitroblue Tetrazolium / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*; D010101:Oxygen Consumption; D010586:Phagocytes / Q000166:cytology / Q000502:physiology; D010873:Pinocytosis; D016897:Respiratory Burst; D013481:Superoxides / Q000378:metabolism; D014561:Urochordata / Q000166:cytology* / Q000502:physiology* / Q000648:ultrastructure
D016023:Integrins; D009842:Oligopeptides; D013481:Superoxides; D009580:Nitroblue Tetrazolium; C047981:arginyl-glycyl-aspartic acid; D000255:Adenosine Triphosphate; C046617:arginyl-glycyl-aspartyl-serine; D006735:Horseradish Peroxidase; D003576:Electron Transport Complex IV