transporter associated with antigen processing
[trænˈspɔ:tə ə'səuʃi wið ˈæntɪdʒən prəʊˈsesɪŋ]
Transporter associated with antigen processing (TAP) is a member of the ATP-binding-cassette transporter family. It delivers cytosolic peptides into the endoplasmic reticulum (ER), where they bind to nascent MHC class I molecules.