Peptide translocation by variants of the transporter associated with antigen processing.
Major histocompatibility complex (MHC) class I molecules associate with peptides that are delivered from the cytosol to the lumen of the endoplasmic reticulum by the transporter associated with antigen processing (TAP). Liver microsomes of SHR and Lewis rats, which express different alleles of TAP (cim(b) and cim(a), respectively), accumulate different sets of peptides. Use of MHC congenic rats assigned this difference to the MHC, independent of the class I products expressed. Both the cim(a) and cim(b) TAP complexes translocate peptides with a hydrophobic carboxyl terminus, but translocation of peptides with a carboxyl-terminal His, Lys, or Arg residue is unique to cim(a). Thus, the specificity of the TAP peptide translocator restricts the peptides available for antigen presentation.
Heemels
M T
MT
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Schumacher
T N
TN
Wonigeit
K
K
Ploegh
H L
HL
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters; D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation / Q000502:physiology*; D001692:Biological Transport / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D015395:Histocompatibility Antigens Class I / Q000502:physiology; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000502:physiology*; D066298:In Vitro Techniques; D008862:Microsomes, Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism*; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D011918:Rats, Inbred SHR; D013379:Substrate Specificity
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D009842:Oligopeptides; C073119:TAP1 protein, human; C486172:Tap1 protein, rat; C489514:Tap2 protein, rat; C071692:TAP2 protein, human