Cargando…
ER-Targeted Beclin 1 Supports Autophagosome Biogenesis in the Absence of ULK1 and ULK2 Kinases
Autophagy transports cytoplasmic material and organelles to lysosomes for degradation and recycling. Beclin 1 forms a complex with several other autophagy proteins and functions in the initiation phase of autophagy, but the exact role of Beclin 1 subcellular localization in autophagy initiation is s...
Autores principales: | , , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2019
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6562811/ https://www.ncbi.nlm.nih.gov/pubmed/31108943 http://dx.doi.org/10.3390/cells8050475 |
_version_ | 1783426408662433792 |
---|---|
author | Anwar, Tahira Liu, Xiaonan Suntio, Taina Marjamäki, Annika Biazik, Joanna Chan, Edmond Y. W. Varjosalo, Markku Eskelinen, Eeva-Liisa |
author_facet | Anwar, Tahira Liu, Xiaonan Suntio, Taina Marjamäki, Annika Biazik, Joanna Chan, Edmond Y. W. Varjosalo, Markku Eskelinen, Eeva-Liisa |
author_sort | Anwar, Tahira |
collection | PubMed |
description | Autophagy transports cytoplasmic material and organelles to lysosomes for degradation and recycling. Beclin 1 forms a complex with several other autophagy proteins and functions in the initiation phase of autophagy, but the exact role of Beclin 1 subcellular localization in autophagy initiation is still unclear. In order to elucidate the role of Beclin 1 localization in autophagosome biogenesis, we generated constructs that target Beclin 1 to the endoplasmic reticulum (ER) or mitochondria. Our results confirmed the proper organelle-specific targeting of the engineered Beclin 1 constructs, and the proper formation of autophagy-regulatory Beclin 1 complexes. The ULK kinases are required for autophagy initiation upstream of Beclin 1, and autophagosome biogenesis is severely impaired in ULK1/ULK2 double knockout cells. We tested whether Beclin 1 targeting facilitated its ability to rescue autophagosome formation in ULK1/ULK2 double knockout cells. ER-targeted Beclin 1 was most effective in the rescue experiments, while mitochondria-targeted and non-targeted Beclin 1 also showed an ability to rescue, but with lower activity. However, none of the constructs was able to increase autophagic flux in the knockout cells. We also showed that wild type Beclin 1 was enriched on the ER during autophagy induction, and that ULK1/ULK2 facilitated the ER-enrichment of Beclin 1 under basal conditions. The results suggest that one of the functions of ULK kinases may be to enhance Beclin 1 recruitment to the ER to drive autophagosome formation. |
format | Online Article Text |
id | pubmed-6562811 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-65628112019-06-17 ER-Targeted Beclin 1 Supports Autophagosome Biogenesis in the Absence of ULK1 and ULK2 Kinases Anwar, Tahira Liu, Xiaonan Suntio, Taina Marjamäki, Annika Biazik, Joanna Chan, Edmond Y. W. Varjosalo, Markku Eskelinen, Eeva-Liisa Cells Article Autophagy transports cytoplasmic material and organelles to lysosomes for degradation and recycling. Beclin 1 forms a complex with several other autophagy proteins and functions in the initiation phase of autophagy, but the exact role of Beclin 1 subcellular localization in autophagy initiation is still unclear. In order to elucidate the role of Beclin 1 localization in autophagosome biogenesis, we generated constructs that target Beclin 1 to the endoplasmic reticulum (ER) or mitochondria. Our results confirmed the proper organelle-specific targeting of the engineered Beclin 1 constructs, and the proper formation of autophagy-regulatory Beclin 1 complexes. The ULK kinases are required for autophagy initiation upstream of Beclin 1, and autophagosome biogenesis is severely impaired in ULK1/ULK2 double knockout cells. We tested whether Beclin 1 targeting facilitated its ability to rescue autophagosome formation in ULK1/ULK2 double knockout cells. ER-targeted Beclin 1 was most effective in the rescue experiments, while mitochondria-targeted and non-targeted Beclin 1 also showed an ability to rescue, but with lower activity. However, none of the constructs was able to increase autophagic flux in the knockout cells. We also showed that wild type Beclin 1 was enriched on the ER during autophagy induction, and that ULK1/ULK2 facilitated the ER-enrichment of Beclin 1 under basal conditions. The results suggest that one of the functions of ULK kinases may be to enhance Beclin 1 recruitment to the ER to drive autophagosome formation. MDPI 2019-05-17 /pmc/articles/PMC6562811/ /pubmed/31108943 http://dx.doi.org/10.3390/cells8050475 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Anwar, Tahira Liu, Xiaonan Suntio, Taina Marjamäki, Annika Biazik, Joanna Chan, Edmond Y. W. Varjosalo, Markku Eskelinen, Eeva-Liisa ER-Targeted Beclin 1 Supports Autophagosome Biogenesis in the Absence of ULK1 and ULK2 Kinases |
title | ER-Targeted Beclin 1 Supports Autophagosome Biogenesis in the Absence of ULK1 and ULK2 Kinases |
title_full | ER-Targeted Beclin 1 Supports Autophagosome Biogenesis in the Absence of ULK1 and ULK2 Kinases |
title_fullStr | ER-Targeted Beclin 1 Supports Autophagosome Biogenesis in the Absence of ULK1 and ULK2 Kinases |
title_full_unstemmed | ER-Targeted Beclin 1 Supports Autophagosome Biogenesis in the Absence of ULK1 and ULK2 Kinases |
title_short | ER-Targeted Beclin 1 Supports Autophagosome Biogenesis in the Absence of ULK1 and ULK2 Kinases |
title_sort | er-targeted beclin 1 supports autophagosome biogenesis in the absence of ulk1 and ulk2 kinases |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6562811/ https://www.ncbi.nlm.nih.gov/pubmed/31108943 http://dx.doi.org/10.3390/cells8050475 |
work_keys_str_mv | AT anwartahira ertargetedbeclin1supportsautophagosomebiogenesisintheabsenceofulk1andulk2kinases AT liuxiaonan ertargetedbeclin1supportsautophagosomebiogenesisintheabsenceofulk1andulk2kinases AT suntiotaina ertargetedbeclin1supportsautophagosomebiogenesisintheabsenceofulk1andulk2kinases AT marjamakiannika ertargetedbeclin1supportsautophagosomebiogenesisintheabsenceofulk1andulk2kinases AT biazikjoanna ertargetedbeclin1supportsautophagosomebiogenesisintheabsenceofulk1andulk2kinases AT chanedmondyw ertargetedbeclin1supportsautophagosomebiogenesisintheabsenceofulk1andulk2kinases AT varjosalomarkku ertargetedbeclin1supportsautophagosomebiogenesisintheabsenceofulk1andulk2kinases AT eskelineneevaliisa ertargetedbeclin1supportsautophagosomebiogenesisintheabsenceofulk1andulk2kinases |