Biomaterial Database

Trimming of TAP-translocated peptides in the endoplasmic reticulum and in the cytosol during recycling. 1994

J Roelse, and M Grommé, and F Momburg, and G Hämmerling, and J Neefjes

The Netherlands Cancer Institute, Amsterdam.

Cytosolic peptides are translocated to the endoplasmic reticulum (ER) lumen by the transporters associated with antigen processing (TAP), where major histocompatibility complex (MHC) class I molecules associate with peptides of about 8-10 amino acids. TAP translocates peptides of 9-13 amino acids with the highest relative affinity but also longer and shorter peptides. The fate of the peptides that fail to associate with class I molecules because of incorrect sequence or length, is unknown. Here we show that the bulk of the translocated peptides are rapidly released from the ER by a mechanism that requires adenosine triphosphate (ATP) and that could not be inhibited by GTP gamma S. TAP does not appear to be involved in this process. Whereas free peptides are slowly trimmed in the ER lumen, they are rapidly degraded in the cytosol. A fraction of the peptides released from the ER escapes complete degradation in the cytosol and recycles back to the ER in a TAP-dependent fashion. These results suggest that peptides that are too long for binding to class I molecules in the ER can be trimmed further in the ER lumen or, alternatively, can be transported back to the cytosol where a fraction of the peptides is trimmed to a size suitable for association to MHC class I molecules and recycles back to the ER.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols
D004721	Endoplasmic Reticulum	A system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)	Ergastoplasm,Reticulum, Endoplasmic
D006031	Glycosylation	The synthetic chemistry reaction or enzymatic reaction of adding carbohydrate or glycosyl groups. GLYCOSYLTRANSFERASES carry out the enzymatic glycosylation reactions. The spontaneous, non-enzymatic attachment of reducing sugars to free amino groups in proteins, lipids, or nucleic acids is called GLYCATION (see MAILLARD REACTION).	Protein Glycosylation,Glycosylation, Protein
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001692	Biological Transport	The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.	Transport, Biological,Biologic Transport,Transport, Biologic
D015395	Histocompatibility Antigens Class I	Membrane glycoproteins consisting of an alpha subunit and a BETA 2-MICROGLOBULIN beta subunit. In humans, highly polymorphic genes on CHROMOSOME 6 encode the alpha subunits of class I antigens and play an important role in determining the serological specificity of the surface antigen. Class I antigens are found on most nucleated cells and are generally detected by their reactivity with alloantisera. These antigens are recognized during GRAFT REJECTION and restrict cell-mediated lysis of virus-infected cells.	Class I Antigen,Class I Antigens,Class I Histocompatibility Antigen,Class I MHC Protein,Class I Major Histocompatibility Antigen,MHC Class I Molecule,MHC-I Peptide,Class I Histocompatibility Antigens,Class I Human Antigens,Class I MHC Proteins,Class I Major Histocompatibility Antigens,Class I Major Histocompatibility Molecules,Human Class I Antigens,MHC Class I Molecules,MHC-I Molecules,MHC-I Peptides,Antigen, Class I,Antigens, Class I,I Antigen, Class,MHC I Molecules,MHC I Peptide,MHC I Peptides,Molecules, MHC-I,Peptide, MHC-I,Peptides, MHC-I
D018528	ATP-Binding Cassette Transporters	A family of MEMBRANE TRANSPORT PROTEINS that require ATP hydrolysis for the transport of substrates across membranes. The protein family derives its name from the ATP-binding domain found on the protein.	ABC Transporter,ABC Transporters,ATP-Binding Cassette Transporter,ATP Binding Cassette Transporter,ATP Binding Cassette Transporters,Cassette Transporter, ATP-Binding,Transporter, ABC,Transporter, ATP-Binding Cassette,Transporters, ABC,Transporters, ATP-Binding Cassette