Transcytosis-associated protein (TAP)/p115 is a general fusion factor required for binding of vesicles to acceptor membranes

Academic Article


  • Transcytosis-associated protein (TAP) is found on transcytotic vesicles (TCVs) and is required for their fusion with the target membrane. We developed a cell-free assay capable of differentiating targeting/binding of TCVs to membrane from later fusion events. We found that TAP mediates stable association of TCVs with the target membrane. The sequence of rat liver TAP (959-amino acid open reading frame) encodes a protein that contains (i) an N- terminal region (amino acids 1-649), (ii) an internal region with several coiled-coil stretches (amino acids 650-930), and (iii) a C-terminal acidic region (amino acids 931-959). Comparisons between TAP and other sequences indicate that TAP is identical to p115, a protein involved in cis to medial Golgi transport, and homologous to Uso1p, a yeast protein involved in endoplasmic reticulum to Golgi transport. Our findings suggest that TAP/p115/Usop1 is a general factor acting within the secretory and endocytic pathways to bind transport vesicles prior to membrane fusion.
  • Digital Object Identifier (doi)

    Pubmed Id

  • 19664980
  • Author List

  • Barroso M; Nelson DS; Sztul E
  • Start Page

  • 527
  • End Page

  • 531
  • Volume

  • 92
  • Issue

  • 2