Phosphorylation of threonine 156 of the mu2 subunit of the AP2 complex is essential for endocytosis in vitro and in vivo.
The clathrin-coated pit is the major port of entry for many receptors and pathogens and is the paradigm for membrane-based sorting events in higher cells [1]. Recently, it has been possible to reconstitute in vitro the events leading to assembly, invagination, and budding off of clathrin-coated vesicles, allowing dissection of the machinery required for sequestration of receptors into these structures [2-6]. The AP2 adaptor complex is a key element of this machinery linking receptors to the coat lattice, and it has previously been reported that AP2 can be phosphorylated both in vitro and in vivo [7-10]. However, the physiological significance of this has never been established. Here, we show that phosphorylation of a single threonine residue (Thr156) of the mu2 subunit of the AP2 complex is essential for efficient endocytosis of transferrin both in an in vitro coated-pit budding assay and in living cells.
Olusanya
O
O
School of Life Sciences, Division of Molecular Cell Biology, Wellcome Trust Biocentre, University of Dundee, DD1 5EH, Scotland, Dundee, United Kingdom.
Andrews
P D
PD
Swedlow
J R
JR
Smythe
E
E
D033961:Adaptor Protein Complex 1; D033962:Adaptor Protein Complex 2; D033963:Adaptor Protein Complex 3; D033983:Adaptor Protein Complex mu Subunits; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D010766:Phosphorylation; D013912:Threonine / Q000378:metabolism*
C499064:AP1M2 protein, human; C510070:AP3M2 protein, human; D033961:Adaptor Protein Complex 1; D033962:Adaptor Protein Complex 2; D033963:Adaptor Protein Complex 3; D033983:Adaptor Protein Complex mu Subunits; D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; D008565:Membrane Proteins; C499065:adaptor protein complex 1, mu 2 subunit; C438886:adaptor protein complex 2, mu 2 subunit; D013912:Threonine