摘要
Autophagy(self-eating)is a self-degradation process essential for survival,differentiation,development,and homeostasis.Conceiving that a process of cellular self-eating could be beneficial may appear bewildering.In its simplest form,however,autophagy is probably a single cell’s adjustment to starvation;the cell is forced to break down part of its own reserves to keep alive until circumstances improve(Mizushima and Klionsky,2007).Based on its mechanism,physiological function,and cargo specificity,autophagy can be classified into at least three forms,chaperone-mediated autophagy,microautophagy,and macroautophagy(Klionsky,2005),among which macroautophagy is the best characterized.Autophagy was discovered in mammalian cells and has been extensively investigated in yeast(Huang and Klionsky,2002).Original studies in yeast Saccharomyces cerevisiae identified a group of autophagy(ATG)genes that are required for survival during starvation(Klionsky et al.,2003).Accumulating evidence indicates that many ATG genes are functionally conserved from yeast to mammals;nevertheless,autophagy is more complicated in multicellular organisms and probably requires factors that are absent in yeast.Until now,little is known about the mechanism of autophagy specific to mammals.In a groundbreaking investigation,Tian et al.(2010)discovered four novel genes particularly required for autophagy in multicellular organisms,and established Caenorhabditis elegans as one of the premier genetic models for uncovering new autophagy genes.The authors also isolated numerous new mutations in genes homologous to yeast autophagy genes,which confirmed the results of the study.These new mutations not only provide a valuable resource for inquiring the structure and function of autophagy proteins,but also set up C.elegans as a preeminent system for investigating the role and regulation of autophagy in multicellular organisms.
