Multiplex image-based autophagy RNAi screening identifies SMCR8 as ULK1 kinase activity and gene expression regulator
- Goethe University School of Medicine, Germany
- Goethe University, Germany
- PerkinElmer, Inc., Germany
Abstract
Autophagy is an intracellular recycling and degradation pathway that depends on membrane trafficking. Rab GTPases are central for autophagy but their regulation especially through the activity of Rab GEFs remains largely elusive. We employed a RNAi screen simultaneously monitoring different populations of autophagosomes and identified 34 out of 186 Rab GTPase, GAP and GEF family members as potential autophagy regulators, amongst them SMCR8. SMCR8 uses overlapping binding regions to associate with C9ORF72 or with a C9ORF72-ULK1 kinase complex holo-assembly, which function in maturation and formation of autophagosomes, respectively. While focusing on the role of SMCR8 during autophagy initiation, we found that kinase activity and gene expression of ULK1 are increased upon SMCR8 depletion. The latter phenotype involved association of SMCR8 with the ULK1 gene locus. Global mRNA expression analysis revealed that SMCR8 regulates transcription of several other autophagy genes including WIPI2. Collectively, we established SMCR8 as multifaceted negative autophagy regulator.
Article and author information
Author details
Christian Behrends
Funding
Deutsche Forschungsgemeinschaft (SFB1177)
- Stefan Müller
- Ivan Dikic
- Christian Behrends
Munich Cluster of Systems Neurology (EXC 1010 SyNergy)
- Christian Behrends
Goethe-Universität Frankfurt am Main (EXC115)
- Ivan Dikic
LOEWE Zentrum (Ub-net)
- Stefan Müller
- Ivan Dikic
- Christian Behrends
European Research Council (ERC,282333-XABA)
- Christian Behrends
Deutsche Forschungsgemeinschaft (DI 931/3-1)
- Ivan Dikic
LOEWE Zentrum (Gene and Cell Therapy Frankfurt)
- Christian Behrends
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2017, Jung et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Multiplex image-based autophagy RNAi screening identifies SMCR8 as ULK1 kinase activity and gene expression regulator
eLife 6:e23063.
https://doi.org/10.7554/eLife.23063
