The TBC/RabGAP Armus Coordinates Rac1 and Rab7 Functions during Autophagy
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Published version
Author(s)
Type
Journal Article
Abstract
Autophagy is an evolutionarily conserved process that enables catabolic and degradative pathways. These pathways commonly depend on vesicular transport controlled by Rabs, small GTPases inactivated by TBC/RabGAPs. The Rac1 effector TBC/RabGAP Armus (TBC1D2A) is known to inhibit Rab7, a key regulator of lysosomal function. However, the precise coordination of signaling and intracellular trafficking that regulates autophagy is poorly understood. We find that overexpression of Armus induces the accumulation of enlarged autophagosomes, while Armus depletion significantly delays autophagic flux. Upon starvation-induced autophagy, Rab7 is transiently activated. This spatiotemporal regulation of Rab7 guanosine triphosphate/guanosine diphosphate cycling occurs by Armus recruitment to autophagosomes via interaction with LC3, a core autophagy regulator. Interestingly, autophagy potently inactivates Rac1. Active Rac1 competes with LC3 for interaction with Armus and thus prevents its appropriate recruitment to autophagosomes. The precise coordination between Rac1 and Rab7 activities during starvation suggests that Armus integrates autophagy with signaling and endocytic trafficking.
Date Issued
2013-04-04
Date Acceptance
2013-03-06
Citation
Developmental Cell, 2013, 25 (1), pp.15-28
ISSN
1878-1551
Publisher
Elsevier
Start Page
15
End Page
28
Journal / Book Title
Developmental Cell
Volume
25
Issue
1
Copyright Statement
Open access under the CC BY license.
License URL
Sponsor
Medical Research Council (MRC)
Cancer Research UK
Grant Number
G0600791
C1282/A11980
Subjects
Science & Technology
Life Sciences & Biomedicine
Cell Biology
Developmental Biology
CELL BIOLOGY
DEVELOPMENTAL BIOLOGY
ENDOPLASMIC-RETICULUM
MAMMALIAN TARGET
CELL-MIGRATION
CANCER
MATURATION
PROTEINS
COMPLEX
GTPASE
ACTIVATION
ATG8
Amino Acid Sequence
Autophagy
Culture Media
Enzyme Activation
Fluorescent Antibody Technique
GTPase-Activating Proteins
Guanosine Triphosphate
Humans
Infant, Newborn
Keratinocytes
Lysosomes
Microtubule-Associated Proteins
Molecular Sequence Data
Phagosomes
Protein Binding
Protein Interaction Mapping
Protein Transport
Signal Transduction
rab GTP-Binding Proteins
rac1 GTP-Binding Protein
06 Biological Sciences
11 Medical And Health Sciences
Publication Status
Published