Question

In the class I MHC pathway of antigen presentation, peptides generated in the cytosol are translocated into the endoplasmic reticulum in which of the following ways?

A. By ATP-dependent transport via the transporter associated with antigen-processing (TAP) 1/2 pump
B. By passive diffusion
C. By receptor-mediated endocytosis
D. Through membrane pores
E. Via the proteasome

Answer 1

Option (A), In the class I MHC pathway, peptides from the cytosol are translocated into the endoplasmic reticulum via ATP-dependent transport with the TAP 1/2 pump for antigen presentation to T cells.

Step-by-step explanation:

In the class I MHC pathway of antigen presentation, peptides generated in the cytosol are translocated into the endoplasmic reticulum by ATP-dependent transport via the transporter associated with antigen-processing (TAP) 1/2 pump.

The TAP complex plays a crucial role in the immune response by transferring cytosolic peptides, after their generation by the proteasome, into the lumen of the endoplasmic reticulum, where they bind to MHC class I molecules. Once bound, the peptide-MHC class I complexes are transported to the cell surface to be presented to T cells.