Interaction of amphiphysins with AP-1 clathrin adaptors at the membrane.
Biochem J
; 450(1): 73-83, 2013 Feb 15.
Article
em En
| MEDLINE
| ID: mdl-23190214
ABSTRACT
The assembly of clathrin/AP (adaptor protein)-1-coated vesicles on the trans-Golgi network and endosomes is much less studied than that of clathrin/AP-2 vesicles at the plasma membrane for endocytosis. In vitro, the association of AP-1 with protein-free liposomes had been shown to require phosphoinositides, Arf1 (ADP-ribosylation factor 1)-GTP and additional cytosolic factor(s). We have purified an active fraction from brain cytosol and found it to contain amphiphysin 1 and 2 and endophilin A1, three proteins known to be involved in the formation of AP-2/clathrin coats at the plasma membrane. Assays with bacterially expressed and purified proteins showed that AP-1 stabilization on liposomes depends on amphiphysin 2 or the amphiphysin 1/2 heterodimer. Activity is independent of the SH3 (Src homology 3) domain, but requires interaction of the WDLW motif with γ-adaptin. Endogenous amphiphysin in neurons and transfected protein in cell lines co-localize perinuclearly with AP-1 at the trans-Golgi network. This localization depends on interaction of clathrin and the adaptor sequence in the amphiphysins and is sensitive to brefeldin A, which inhibits Arf1-dependent AP-1 recruitment. Interaction between AP-1 and amphiphysin 1/2 in vivo was demonstrated by co-immunoprecipitation after cross-linking. These results suggest an involvement of amphiphysins not only with AP-2 at the plasma membrane, but also in AP-1/clathrin coat formation at the trans-Golgi network.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Proteínas Nucleares
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Membrana Celular
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Clatrina
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Proteínas Supressoras de Tumor
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Complexo 1 de Proteínas Adaptadoras
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Proteínas Adaptadoras de Transdução de Sinal
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Proteínas do Tecido Nervoso
Limite:
Animals
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Humans
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article