Fig. 1

Types of autophagy. Autophagy can be divided into macroautophagy, microautophagy and chaperon-mediated autophagy (CMA) [16]. Macroautophagy is a highly conserved cellular process that involves the formation of autophagosome via sequestration of a portion of a cellular component to form autophagosome [39]. Fusion of autophagosome and lysosome forms autolysosome in which degradation of macromolecules and dysfunctional cellular organelles would take place [16]. Microautophagy involves the engulfment of a vesicle by lysosome via cytoplasmic invagination [42]. CMA is a type of highly selective autophagy in which only specific macromolecules that are tagged with a special C-terminal KFERQ motif will be recognized by specific chaperon protein (HSC70), this will then facilitate the binding of the selected macromolecules to the LAMP-A2 protein on the lysosome surface for autophagy to happen [43]