Intracellular location, complex formation, and function of the transporter associated with antigen processing in yeast.
Peptide transport across the membrane of the endoplasmic reticulum (ER) gains increasing importance in view of its potential function in selective protein degradation and antigen processing. An example for peptide transport in the ER is the transporter associated with antigen processing (TAP), which supplies peptides for the formation of major-histocompatibility-complex class-I complexes. Here, we have expressed human TAP1 and TAP2 in the yeast Saccharomyces cerevisiae. Expression of both genes resulted in the formation of a stable TAP heterodimer that was localized mainly in the ER. Although a minor fraction of TAP is found in the plasma membrane, TAP is unable to restore a-factor secretion in a mutant cell line that lacks the yeast mating-factor transporter Ste6. Nevertheless, in vitro studies with microsomal vesicles demonstrated that the TAP complex is fully functional in the ER membrane in terms of selective peptide binding, ATP-dependent transport, and specific inhibition by the viral protein of herpes simplex virus ICP47. This offers opportunities for topological, structural and mechanistic studies as well as genetic screenings for TAP functionality.
Urlinger
S
S
Max-Planck-Institut für Biochemie, Martinsried, Germany.
Kuchler
K
K
Meyer
T H
TH
Uebel
S
S
Tampé
R
R
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D026905:Amino Acid Transport Systems; D017951:Antigen Presentation / Q000187:drug effects / Q000502:physiology*; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D006023:Glycoproteins; D006801:Humans; D017874:Immediate-Early Proteins / Q000494:pharmacology; D046911:Macromolecular Substances; D008285:Major Histocompatibility Complex / Q000502:physiology*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014764:Viral Proteins
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters; D026905:Amino Acid Transport Systems; D005656:Fungal Proteins; D006023:Glycoproteins; C105843:ICP47 protein, Herpes simplex virus; D017874:Immediate-Early Proteins; D046911:Macromolecular Substances; C489277:STE6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C073119:TAP1 protein, human; C429825:TAT2 protein, S cerevisiae; D014764:Viral Proteins; C071692:TAP2 protein, human