Phosphorylation of threonine 156 of the mu2 subunit of the AP2 complex is essential for endocytosis in vitro and in vivo

Curr Biol. 2001 Jun 5;11(11):896-900. doi: 10.1016/s0960-9822(01)00240-8.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Protein Complex 1*
  • Adaptor Protein Complex 2
  • Adaptor Protein Complex 3*
  • Adaptor Protein Complex mu Subunits*
  • Adaptor Proteins, Vesicular Transport
  • Animals
  • Carrier Proteins / metabolism*
  • Cattle
  • Coated Pits, Cell-Membrane / metabolism*
  • Endocytosis / physiology*
  • HeLa Cells
  • Humans
  • Membrane Proteins / metabolism*
  • Phosphorylation
  • Threonine / metabolism*


  • AP1M2 protein, human
  • AP3M2 protein, human
  • Adaptor Protein Complex 1
  • Adaptor Protein Complex 2
  • Adaptor Protein Complex 3
  • Adaptor Protein Complex mu Subunits
  • Adaptor Proteins, Vesicular Transport
  • Carrier Proteins
  • Membrane Proteins
  • adaptor protein complex 1, mu 2 subunit
  • adaptor protein complex 2, mu 2 subunit
  • Threonine