The Role of Macroautophagy in T Cells
The highly conserved self-digestion pathway macroautophagy (hereafter referred to as autophagy) maintains the homeostasis of organelles, degrades long-lived proteins, and recycles amino acids under starvation conditions. Autophagy related molecules are expressed in T lymphocytes, and autophagy occurs inside T lymphocytes. Autophagy-deficient T lymphocytes, which are generated through the deletion of autophagy related molecules, show expansion of organelles content, increased cell death mediated by apoptosis, proliferation defects, instability of the Treg cell lineage, and defect of memory T cell formation. Several different mouse genetic deficiency models show very similar phenotypes. Thus, autophagy plays multiple roles in the regulation of the physiological functions of T lymphocytes. However, how TCR signaling contributes to the initiation of autophagy in T cells and how T cell functions will be affected if autophagy is modified still need to be further investigated.