What is the role of TAP in antigen presentation?
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The transporter associated with antigen processing (TAP) is essential for peptide delivery from the cytosol into the lumen of the endoplasmic reticulum (ER), where these peptides are loaded on major histocompatibility complex (MHC) I molecules.
What do tap proteins do?
Transporter associated with antigen processing (TAP) protein complex belongs to the ATP-binding-cassette transporter family. It delivers cytosolic peptides into the endoplasmic reticulum (ER), where they bind to nascent MHC class I molecules.
Which cell type is primarily responsible for antigen processing?
The main antigen presenting cells in the early immune response are monocytes/macrophages and dendritic cells (DC), including their tissue resident subtypes.
Which MHC uses tap?
MHC class I
Most strikingly, MHC class I molecules are found in close association with the TAP complex [110], [111]. As reported by Powis, MHC class I molecules interact with TAP1 and TAP2 [112]. Approximately four MHC class I molecules seem to be linked via four tapasins to one TAP complex [58].
How are antigens processed and presented?
The usual process of antigen presentation through the MHC I molecule is based on an interaction between the T-cell receptor and a peptide bound to the MHC class I molecule. There is also an interaction between the CD8+ molecule on the surface of the T cell and non-peptide binding regions on the MHC class I molecule.
What is the characteristics feature of TAP deficiency?
Although asymptomatic cases have been described, TAP deficiencies are usually characterized by chronic bacterial infections of the upper and lower airways, evolving to bronchiectasis, and in half of the cases, also skin ulcers with features of a chronic granulomatous inflammation.
What are antigen-presenting cells?
Definition. Antigen-presenting cells (APCs) are a heterogeneous group of immune cells that mediate the cellular immune response by processing and presenting antigens for recognition by certain lymphocytes such as T cells. Classical APCs include dendritic cells, macrophages, Langerhans cells and B cells.
What is an antigen processing cell?
Antigen processing, or the cytosolic pathway, is an immunological process that prepares antigens for presentation to special cells of the immune system called T lymphocytes. It is considered to be a stage of antigen presentation pathways.
What typically processes exogenous antigens?
Exogenous proteins, however, are primarily presented by MHC-II molecules. Antigens are internalized by several pathways, including phagocytosis, macropinocytosis, and endocytosis, and eventually traffic to a mature or late endosomal compartment where they are processed and loaded onto MHC-II molecules.
What are TAP genes?
The TAP1 gene provides instructions for making a protein that plays an important role in the immune system. The TAP1 protein assembles with another protein called TAP2 (produced from the TAP2 gene) to form a protein complex called transporter associated with antigen processing (TAP) complex.
How does antigen processing work?
Antigen processing and presentation is the process by which protein antigen is ingested by an antigen-presenting cell (APC), partially digested into peptide fragments and then displayed on the surface of the APC associated with an antigen-presenting molecule such as MHC class I or MHC class II, for recognition by …