Clathrin-dependent mechanisms modulate the subcellular distribution of class C Vps/HOPS tether subunits in polarized and nonpolarized cells

Mol Biol Cell. 2011 May 15;22(10):1699-715. doi: 10.1091/mbc.E10-10-0799. Epub 2011 Mar 16.

Abstract

Coats define the composition of carriers budding from organelles. In addition, coats interact with membrane tethers required for vesicular fusion. The yeast AP-3 (Adaptor Protein Complex 3) coat and the class C Vps/HOPS (HOmotypic fusion and Protein Sorting) tether follow this model as their interaction occurs at the carrier fusion step. Here we show that mammalian Vps class C/HOPS subunits and clathrin interact and that acute perturbation of clathrin function disrupts the endosomal distribution of Vps class C/HOPS tethers in HEK293T and polarized neuronal cells. Vps class C/HOPS subunits and clathrin exist in complex with either AP-3 or hepatocyte growth factor receptor substrate (Hrs). Moreover, Vps class C/HOPS proteins cofractionate with clathrin-coated vesicles, which are devoid of Hrs. Expression of FK506 binding protein (FKBP)-clathrin light chain chimeras, to inhibit clathrin membrane association dynamics, increased Vps class C/HOPS subunit content in rab5 endosomal compartments. Additionally, Vps class C/HOPS subunits were concentrated at tips of neuronal processes, and their delivery was impaired by expression of FKBP-clathrin chimeras and AP20187 incubation. These data support a model in which Vps class C/HOPS subunits incorporate into clathrin-coated endosomal domains and carriers in mammalian cells. We propose that vesicular (AP-3) and nonvesicular (Hrs) clathrin mechanisms segregate class C Vps/HOPS tethers to organelles and domains of mammalian cells bearing complex architectures.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptor Protein Complex 3 / metabolism
  • Adaptor Protein Complex delta Subunits / metabolism
  • Animals
  • Cell Line
  • Cell Polarity*
  • Clathrin / antagonists & inhibitors
  • Clathrin / genetics
  • Clathrin / metabolism*
  • Clathrin-Coated Vesicles / drug effects
  • Clathrin-Coated Vesicles / metabolism
  • Endosomes / drug effects
  • Endosomes / metabolism
  • Humans
  • Immunoprecipitation
  • Multiprotein Complexes / metabolism
  • Neurons / metabolism
  • Protein Binding
  • Protein Subunits / metabolism
  • Rats
  • Recombinant Fusion Proteins / metabolism
  • Tacrolimus / analogs & derivatives
  • Tacrolimus / pharmacology
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism*
  • rab GTP-Binding Proteins / metabolism

Substances

  • AP20187
  • AP3D1 protein, human
  • Adaptor Protein Complex 3
  • Adaptor Protein Complex delta Subunits
  • Clathrin
  • Multiprotein Complexes
  • Protein Subunits
  • Recombinant Fusion Proteins
  • Vesicular Transport Proteins
  • rab GTP-Binding Proteins
  • Tacrolimus