Autophagy: The Powerful of Immune Response

No Thumbnail Available
Journal Title
Journal ISSN
Volume Title
Introduction Autophagy is an intracellular degradation system that delivers cytoplasmic constituents to the lysosome. Despite its simplicity, recent progress has demonstrated that autophagy plays a wide variety of physiological and pathophysiological roles, which are sometimes complex. Autophagy consists of several sequential steps sequestration, transport to lysosomes, degradation, and utilization of degradation products and each step may exert different function. This process is quite distinct from endocytosis-mediated lysosomal degradation of extracellular and plasma membrane proteins. There are three types of autophagy macroautophagy, micro autophagy, and chaperone-mediated autophagy and the term “autophagy” usually indicates macroautophagy unless otherwise specified. Autophagy is mediated by a unique organelle called the autophagosome. As autophagosomes engulf a portion of cytoplasm, autophagy is generally thought to be a nonselective degradation system. This feature is in marked contrast to the ubiquitin-proteasome system, which specifically recognizes only ubiquitinated proteins for proteasomal degradation. It is therefore reasonable to assume that the ubiquitin-proteasome system has numerous specific functions because it can selectively degrade thousands of substrates. Recent studies have clearly demonstrated that autophagy has a greater variety of physiological and pathophysiological roles than expected, such as starvation adaptation, intracellular protein and organelle clearance, development, anti-aging, elimination of microorganisms, cell death, tumor suppression, and antigen presentation. Additionally, in some situations, the contribution of autophagy seems to be very complicated. For example, it is very difficult to generalize the role of autophagy in cancer and cell death [1].