MERIT, a cellular system coordinating lysosomal repair, removal and replacement.

MERIT, a cellular system coordinating lysosomal repair, removal and replacement. Autophagy. 2020 Jun 10;: Authors: Jia J, Claude-Taupin A, Gu Y, Choi SW, Peters R, Bissa B, Mudd MH, Allers L, Pallikkuth S, Lidke KA, Salemi M, Phinney B, Mari M, Reggiori F, Deretic V Abstract Membrane integrity is essential for cellular survival and function. The spectrum of mechanisms protecting cellular and intracellular membranes is not fully known. Our recent work has uncovered a cellular system termed MERIT for lysosomal membrane repair, removal and replacement. Specifically, lysosomal membrane damage induces, in succession, ESCRT-dependent membrane repair, macroautophagy/autophagy-dominant removal of damaged lysosomes, and initiation of lysosomal biogenesis via transcriptional programs. The MERIT system is governed by galectins, a family of cytosolically synthesized lectins recognizing β-galactoside glycans. We found in this study that LGALS3 (galectin 3) detects membrane damage by detecting exposed lumenal glycosyl groups, recruits and organizes ESCRT components PDCD6IP/ALIX, CHMP4A, and CHMPB at damaged sites on the lysosomes, and facilitates ESCRT-driven repair of lysosomal membrane. At later stages, LGALS3 cooperates with TRIM16, an autophagy receptor-regulator, to engage autophagy machinery in removal of excessively damaged lysosomes. In the absence of LGALS3, repair and autophagy are less efficient, whereas TFEB nuclear translocation incr...
Source: Autophagy - Category: Cytology Authors: Tags: Autophagy Source Type: research