A burst of auxilin recruitment determines the onset of clathrin-coated vesicle uncoating.
Clathrin-coated pits assemble on a membrane and pinch off as coated vesicles. The released vesicles then rapidly lose their clathrin coats in a process mediated by the ATPase Hsc70, recruited by auxilin, a J-domain-containing cofactor. How is the uncoating process regulated? We find that during coat assembly small and variable amounts of auxilin are recruited transiently but that a much larger burst of association occurs after the peak of dynamin signal, during the transition between membrane constriction and vesicle budding. We show that the auxilin burst depends on domains of the protein likely to interact with lipid head groups. We conclude that the timing of auxilin recruitment determines the onset of uncoating. We propose that, when a diffusion barrier is established at the constricting neck of a fully formed coated pit and immediately after vesicle budding, accumulation of a specific lipid can recruit sufficient auxilin molecules to trigger uncoating.
Massol
Ramiro H
RH
Department of Cell Biology and CBR Institute for Biomedical Research, Harvard Medical School, 200 Longwood Ave, Boston, MA 02115.
Boll
Werner
W
Department of Cell Biology and CBR Institute for Biomedical Research, Harvard Medical School, 200 Longwood Ave, Boston, MA 02115.
Griffin
April M
AM
Department of Cell Biology and CBR Institute for Biomedical Research, Harvard Medical School, 200 Longwood Ave, Boston, MA 02115.
Kirchhausen
Tomas
T
Department of Cell Biology and CBR Institute for Biomedical Research, Harvard Medical School, 200 Longwood Ave, Boston, MA 02115 kirchhausen@crystal.harvard.edu.
D000818:Animals; D034021:Auxilins / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D022163:Clathrin-Coated Vesicles / Q000378:metabolism*; D034285:Dynamin II / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
D034021:Auxilins; D017346:Protein Serine-Threonine Kinases; D051059:PTEN Phosphohydrolase; D034285:Dynamin II