Biomaterial Database

Soluble tapasin restores MHC class I expression and function in the tapasin-negative cell line .220. 1998

P J Lehner, and M J Surman, and P Cresswell

Section of Immunobiology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06510, USA.

Tapasin forms a bridge between TAP (transporters associated with antigen processing) and MHC class I molecules and plays a critical role in class I assembly. In its absence, TAP and class I do not associate, and class I cell surface expression is reduced. We now identify two independent functions for tapasin. Tapasin increases TAP levels and allows more peptide to be translocated to the endoplasmic reticulum. Furthermore, when expressed in the tapasin-negative .220 cell line, recombinant soluble tapasin retains its association with class I and restores class I cell surface expression and function, even though it no longer binds TAP or increases TAP levels. This finding suggests that the association of tapasin with class I is sufficient to facilitate loading and assembly of class I molecules.

UI	MeSH Term	Description	Entries
D007136	Immunoglobulins	Multi-subunit proteins which function in IMMUNITY. They are produced by B LYMPHOCYTES from the IMMUNOGLOBULIN GENES. They are comprised of two heavy (IMMUNOGLOBULIN HEAVY CHAINS) and two light chains (IMMUNOGLOBULIN LIGHT CHAINS) with additional ancillary polypeptide chains depending on their isoforms. The variety of isoforms include monomeric or polymeric forms, and transmembrane forms (B-CELL ANTIGEN RECEPTORS) or secreted forms (ANTIBODIES). They are divided by the amino acid sequence of their heavy chains into five classes (IMMUNOGLOBULIN A; IMMUNOGLOBULIN D; IMMUNOGLOBULIN E; IMMUNOGLOBULIN G; IMMUNOGLOBULIN M) and various subclasses.	Globulins, Immune,Immune Globulin,Immune Globulins,Immunoglobulin,Globulin, Immune
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
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
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
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
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000071181	ATP Binding Cassette Transporter, Subfamily B, Member 2	An ATP-binding cassette, sub-family B protein (ATP BINDING CASSETTE TRANSPORTER, SUBFAMILY B) that functions in the transport of ANTIGENS from the CYTOPLASM to the ENDOPLASMIC RETICULUM for association with HISTOCOMPATIBILITY ANTIGENS CLASS I peptides. It also acts as a molecular scaffold for the final stage of MHC class I PROTEIN FOLDING.	ABCB2 Protein,ATP Binding Cassette Transporter, Sub-Family B, Member 2,ATP-Binding Cassette Sub-Family B Member 2,Antigen Peptide Transporter-1,Peptide Transporter PSF1,Peptide Transporter TAP1,RING4 Protein,Really Interesting New Gene 4 Protein,TAP-1 Protein,TAP1 Protein,Transporter 1, ATP-Binding Cassette, Sub-Family B (MDR-TAP),ATP Binding Cassette Sub Family B Member 2,Antigen Peptide Transporter 1,PSF1, Peptide Transporter,TAP 1 Protein,TAP1, Peptide Transporter
D000071450	ATP Binding Cassette Transporter, Subfamily B, Member 3	ATP-binding cassette, subfamily B, protein that functions in the transport of ANTIGENS from the CYTOPLASM to the ENDOPLASMIC RETICULUM for association with HISTOCOMPATIBILITY ANTIGENS CLASS I peptides. It functions as a heterodimer with ATP BINDING CASSETTE TRANSPORTER, SUBFAMILY B, MEMBER 2.	ABCB3 Protein,ATP Binding Cassette Transporter, Sub-Family B, Member 3,ATP-Binding Cassette, Sub-Family B, Member 3,Antigen Peptide Transporter-2,Peptide Supply Factor 2,Peptide Transporter Tap2,Antigen Peptide Transporter 2,Tap2, Peptide Transporter
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
D012995	Solubility	The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Solubilities