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Visualizing Autophagic Lysosome Reformation in Cells Using In Vitro Reconstitution Systems

Curr Protoc Cell Biol. 2018 Mar;78(1):11.24.1-11.24.15. doi: 10.1002/cpcb.44.

Abstract

Autophagy is a lysosome-based degradation pathway. Autophagic lysosome reformation (ALR) is a lysosomal membrane recycling process that marks the terminal step of autophagy. During ALR, LAMP1-positive tubules, named reformation tubules, are extruded from autolysosomes, and nascent lysosomes are generated from these tubules. By combining proteomic analysis of purified autolysosomes and RNA interference screening of identified candidates, we systematically elucidated the ALR pathway at the molecular level. Based on the key components clathrin, PtdIns(4,5)P2 , and the motor protein KIF5B, among others, we reconstituted this process in vitro. This unit describes a detailed method for visualizing ALR in cells during the autophagy process. This unit also present a protocol for reconstituting the ALR tubular protrusion and elongation process in vitro and three methods for preparing materials for in vitro reconstitution: (1) autolysosome purification from cultured cells, (2) liposome preparation, and (3) KIF5B purification and quality testing. © 2018 by John Wiley & Sons, Inc.

Keywords: autolysosome purification; autophagic lysosome reformation (ALR); autophagy; density-gradient centrifugation; in vitro reconstitution; liposome preparation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy*
  • Cytological Techniques / methods*
  • HeLa Cells
  • Humans
  • Image Processing, Computer-Assisted
  • Kinesins / metabolism
  • Liposomes
  • Lysosomes / metabolism*
  • Mice
  • Microtubules / metabolism
  • NIH 3T3 Cells
  • Rats

Substances

  • Liposomes
  • Kinesins