Major histocompatibility complex class II-peptide complexes internalize using a clathrin- and dynamin-independent endocytosis pathway

J Biol Chem. 2008 May 23;283(21):14717-27. doi: 10.1074/jbc.M801070200. Epub 2008 Mar 31.

Abstract

Major histocompatibility complex (MHC) class II molecules (MHC-II) function by binding antigenic peptides and displaying these peptides on the surface of antigen presenting cells (APCs) for recognition by peptide-MHC-II (pMHC-II)-specific CD4 T cells. It is known that cell surface MHC-II can internalize, exchange antigenic peptides in endosomes, and rapidly recycle back to the plasma membrane; however, the molecular machinery and trafficking pathways utilized by internalizing/recycling MHC-II have not been identified. We now demonstrate that unlike newly synthesized invariant chain-associated MHC-II, mature cell surface pMHC-II complexes internalize following clathrin-, AP-2-, and dynamin-independent endocytosis pathways. Immunofluorescence microscopy of MHC-II expressing HeLa-CIITA cells, human B cells, and human DCs revealed that pMHC enters Arf6(+)Rab35(+)EHD1(+) tubular endosomes following endocytosis. These data contrast the internalization pathways followed by newly synthesized and peptide-loaded MHC-II molecules and demonstrates that cell surface pMHC-II internalize and rapidly recycle from early endocytic compartments in tubular endosomes.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP-Ribosylation Factor 6
  • ADP-Ribosylation Factors / metabolism
  • Adaptor Protein Complex 2 / genetics
  • Adaptor Protein Complex 2 / metabolism
  • Antigen Presentation / immunology
  • Clathrin / genetics
  • Clathrin / metabolism
  • Dynamins / metabolism
  • Endocytosis*
  • HeLa Cells
  • Histocompatibility Antigens Class II / chemistry
  • Histocompatibility Antigens Class II / immunology*
  • Histocompatibility Antigens Class II / metabolism*
  • Humans
  • Kinetics
  • Peptides / chemistry*
  • rab GTP-Binding Proteins / metabolism

Substances

  • ADP-Ribosylation Factor 6
  • Adaptor Protein Complex 2
  • Clathrin
  • Histocompatibility Antigens Class II
  • Peptides
  • RAB35 protein, human
  • ADP-Ribosylation Factors
  • ARF6 protein, human
  • rab GTP-Binding Proteins
  • Dynamins