Mechanism Of Atg5-Atg12 Complex Degradation In Saccharomyces Cerevisiae

In eukaryotes,Atg5 forms a complex with Atg12.In Saccharomyces cerevisiae,the Atg5-Atg12 complex was degraded,and this degradation occurred under both nutrition and starvation conditions.First we treated cells with cycloheximide and found Atg5-Atg12 complex would be degraded after 1h cycloheximide treatment.Subsequently,atg13△ and atg14△ did not inhibit the degradation of the Atg5-Atg12 complex,and the Dox-induced low expression of the proteasome component pre6 inhibited the degradation of the complex.We knocked out the ATG5,ATG7 and ATG12 genes,Atg12 p degraded faster than Atg5 p.We mainly study the degradation mechanism of Atg5-Atg12 complex by nitrogen starvation.We found knockout of essential genes for autophagy did not inhibit the degradation of the Atg5-Atg12 complex,while the low expression of pre6 inhibited the degradation of the complex,indicating that the Atg5-Atg12 complex was degraded by the proteasome.Under nitrogen starvation,atg1△ inhibited the degradation of the Atg5-Atg12 complex,suggesting that Atg1 may promote its degradation by phosphorylating the Atg5-Atg12 complex.The knockout of PEP5 and PSH1 would inhibit autophagy.In summary,the phosphorylation of Atg5-Atg12 by Atg1 promotes the Atg5-Atg12 proteasome-dependent degradation under starvation Atg5-Atg12 Similarly,the degradation of Atg5-Atg12 under nutritional conditions was also proteasome-dependent,but not Atg1-dependent.