biostudies-literatureGeng JNIGMS NIH HHS129-40https://www.ebi.ac.uk/biostudies/studies/S-EPMC2447896biostudies-literatureUnknown182(1)In yeast, approximately 31 autophagy-related (Atg) proteins have been identified. Most of them reside at the phagophore assembly site (PAS), although the function of the PAS mostly remains unclear. One reason for the latter is the lack of stoichiometric information regarding the Atg proteins at this site. We report the application of fluorescence microscopy to study the amount of Atg proteins at the PAS. We find that an increase in the amount of Atg11 at the PAS enhances the recruitment of Atg8 and Atg9 to this site and facilitates the formation of more cytoplasm-to-vacuole targeting vesicles. In response to autophagy induction, the amount of most Atg proteins remains unchanged at the PAS, whereas we see an enhanced recruitment of Atg8 and 9 at this site. During autophagy, the amount of AtThe Journal of cell biologyQuantitative analysis of autophagy-related protein stoichiometry by fluorescence microscopy.PMC2447896R01 GM053396GM53396Nair UKlionsky DJGeng JBaba MfalseQuantitative analysis of autophagy-related protein stoichiometry by fluorescence microscopy.In yeast, approximately 31 autophagy-related (Atg) proteins have been identified. Most of them reside at the phagophore assembly site (PAS), although the function of the PAS mostly remains unclear. One reason for the latter is the lack of stoichiometric information regarding the Atg proteins at this site. We report the application of fluorescence microscopy to study the amount of Atg proteins at the PAS. We find that an increase in the amount of Atg11 at the PAS enhances the recruitment of Atg8 and Atg9 to this site and facilitates the formation of more cytoplasm-to-vacuole targeting vesicles. In response to autophagy induction, the amount of most Atg proteins remains unchanged at the PAS, whereas we see an enhanced recruitment of Atg8 and 9 at this site. During autophagy, the amount of At2008-01-01T00:00:00Z2008 Jul2025-04-04T18:33:49.295Z2019-03-27T00:15:46ZS-EPMC24478961862584610.1083/jcb.200711112