The interface between tapasin and MHC class I: identification of amino acid residues in both proteins that influence their interaction.
Prior to the binding of antigenic peptide, a complex of chaperone proteins associates with the Major Histocompatibility Complex (MHC) class I heavy chain/beta2m heterodimer. Although each domain of the MHC class I heavy chain contains amino acid residues that influence chaperone binding, there are several pieces of evidence that point to an interaction between the MHC class I alpha/2/alpha3 domains and tapasin. In regard to the site on tapasin involved in the tapasin/MHC interface, we have found that a particular region of tapasin (containing amino acid residues 334-342) is necessary for the binding of tapasin to the MHC class I heavy chain. Our results also indicate that amino acids in this region of tapasin also affect the proportion of MHC class I open forms expressed at the cell surface and MHC class I egress from the endoplasmic reticulum. Based on these results and those obtained by other laboratories, a model for MHC class I/tapasin interaction is proposed.
Turnquist
Hĕth R
HR
Eppley Institute for Research in Cancer and Allied Diseases, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha 68198-6805, USA.
Vargas
Shanna E
SE
Schenk
Erin L
EL
McIlhaney
Mary M
MM
Reber
Adrian J
AJ
Solheim
Joyce C
JC
D000596:Amino Acids; D000818:Animals; D017951:Antigen Presentation; D017920:Antiporters / Q000737:chemistry* / Q000378:metabolism*; D001402:B-Lymphocytes; D002460:Cell Line; D015395:Histocompatibility Antigens Class I / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D007136:Immunoglobulins / Q000737:chemistry* / Q000378:metabolism*; D026901:Membrane Transport Proteins; D051379:Mice; D018832:Molecular Chaperones
D000596:Amino Acids; D017920:Antiporters; D015395:Histocompatibility Antigens Class I; D007136:Immunoglobulins; D026901:Membrane Transport Proteins; D018832:Molecular Chaperones; C107762:tapasin