Dynamin at actin tails.
Dynamin, the product of the shibire gene of Drosophila, is a GTPase critically required for endocytosis. Some studies have suggested a functional link between dynamin and the actin cytoskeleton. This link is of special interest, because there is evidence implicating actin dynamics in endocytosis. Here we show that endogenous dynamin 2, as well as green fluorescence protein fusion proteins of both dynamin 1 and 2, is present in actin comets generated by Listeria or by type I PIP kinase (PIPK) overexpression. In PIPK-induced tails, dynamin is further enriched at the interface between the tails and the moving organelles. Dynamin mutants harboring mutations in the GTPase domain inhibited nucleation of actin tails induced by PIPK and moderately reduced their speed. Although dynamin localization to the tails required its proline-rich domain, expression of a dynamin mutant lacking this domain also diminished tail formation. In addition, this mutant disrupted a membrane-associated actin scaffold (podosome rosette) previously shown to include dynamin. These findings suggest that dynamin is part of a protein network that controls nucleation of actin from membranes. At endocytic sites, dynamin may couple the fission reaction to the polymerization of an actin pool that functions in the separation of the endocytic vesicles from the plasma membrane.
Lee
Eunkyung
E
Department of Cell Biology and Howard Hughes Medical Institute, Yale University School of Medicine, P.O. Box 9812, New Haven, CT 06536-0812, USA.
De Camilli
Pietro
P
D000199:Actins / Q000737:chemistry* / Q000502:physiology*; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D006224:Cricetinae; D003599:Cytoskeleton / Q000737:chemistry; D029721:Drosophila Proteins; D034284:Dynamin I; D034281:Dynamins; D004705:Endocytosis; D020558:GTP Phosphohydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D008089:Listeria monocytogenes / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009154:Mutation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D011392:Proline / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection
D000199:Actins; D029721:Drosophila Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D011392:Proline; D017853:Phosphotransferases (Alcohol Group Acceptor); C020077:1-phosphatidylinositol-4-phosphate 5-kinase; D034284:Dynamin I; D020558:GTP Phosphohydrolases; D034281:Dynamins; C439628:shi protein, Drosophila