Protein trafficking in immune cells.
The majority of cells of the immune system are specialized secretory cells, whose function depends on regulated exocytosis. The latter is mediated by vesicular transport involving the sorting of specialized cargo into the secretory granules (SGs), thereby generating the transport vesicles; their transport along the microtubules and eventually their signal-dependent fusion with the plasma membrane. Each of these steps is tightly controlled by mechanisms, which involve the participation of specific sorting signals on the cargo proteins and their recognition by cognate adaptor proteins, posttranslational modifications of the cargo proteins and multiple GTPases and SNARE proteins. In some of the cells (i.e. mast cells, T killer cells) an intimate connection exists between the secretory system and the endocytic one, whereby the SGs are lysosome related organelles (LROs) also referred to as secretory lysosomes. Herein, we discuss these mechanisms in health and disease states.
Benado
Anat
A
Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
Nasagi-Atiya
Yafit
Y
Sagi-Eisenberg
Ronit
R
D000818:Animals; D005089:Exocytosis / Q000276:immunology; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006801:Humans; D007107:Immune System / Q000473:pathology / Q000502:physiology*; D008247:Lysosomes; D011499:Protein Processing, Post-Translational; D021382:Protein Sorting Signals; D021381:Protein Transport / Q000276:immunology*; D050600:SNARE Proteins / Q000378:metabolism; D022142:Secretory Vesicles / Q000276:immunology*; D020691:rab GTP-Binding Proteins / Q000378:metabolism
D021382:Protein Sorting Signals; D050600:SNARE Proteins; D020558:GTP Phosphohydrolases; D020691:rab GTP-Binding Proteins