VPS37A directs ESCRT recruitment for phagophore closure

The process of phagophore closure requires the endosomal sorting complex required for transport III (ESCRT-III) subunit CHMP2A and the AAA ATPase VPS4, but their regulatory mechanisms remain unknown. Here, we establish a FACS-based HaloTag-LC3 autophagosome completion assay to screen a genome-wide CRISPR library and identify the ESCRT-I subunit VPS37A as a critical component for phagophore closure. VPS37A localizes on the phagophore through the N-terminal putative ubiquitin E2 variant domain, which is found to be required for autophagosome completion but dispensable for ESCRT-I complex formation and the degradation of epidermal growth factor receptor in the multivesicular body pathway. Notably, loss of VPS37A abrogates the phagophore recruitment of the ESCRT-I subunit VPS28 and CHMP2A, whereas inhibition of membrane closure by CHMP2A depletion or VPS4 inhibition accumulates VPS37A on the phagophore. These observations suggest that VPS37A coordinates the recruitment of a unique set of ESCRT machinery components for phagophore closure in mammalian cells.

Source: Journal of Cell Biology - October 6, 2019 Category: Cytology Authors: Takahashi, Y., Liang, X., Hattori, T., Tang, Z., He, H., Chen, H., Liu, X., Abraham, T., Imamura-Kawasawa, Y., Buchkovich, N. J., Young, M. M., Wang, H.-G. Tags: Cell Death and Autophagy, Biochemistry Articles Source Type: research