Specific autophagy and ESCRT components participate in the unconventional secretion of CFTR

Shin Hye Noh, Heon Yung Gee, Yonjung Kim, He Piao, Jiyoon Kim, Chung Min Kang, Gahyung Lee, Inhee Mook-Jung, Yangsin Lee, Jin Won Cho, Min Goo Lee

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The most common mutation in cystic fibrosis patients is a phenylalanine deletion at position 508 (ΔF508) in the CFTR (cystic fibrosis transmembrane conductance regulator) gene. This mutation impairs cell-surface trafficking of CFTR. During cellular stress, core-glycosylated CFTRΔF508 is transported to the cell surface from the endoplasmic reticulum (ER) via an unconventional route that bypasses the Golgi. However, the mechanisms for this unconventional secretory pathway of CFTR are not well delineated. Here, we report that components of the macroautophagy/autophagy and ESCRT (endosomal sorting complex required for transport) pathways are involved in unconventional secretion of CFTR. In mammalian cells, we found that autophagic pathways were modulated by conditions that also stimulate unconventional secretion, namely ER stress and an ER-to-Golgi transport blockade. Additionally, we found that knockdown of early autophagy components, ATG5 and ATG7, and treatment with pharmacological autophagy inhibitors, wortmannin and 3-methyladenine, abolished the unconventional secretion of CFTR that had been stimulated by ER stress and an ER-to-Golgi blockade. Interestingly, immunoelectron microscopy revealed that GORASP2/GRASP55, which mediates unconventional CFTR trafficking, is present in multivesicular bodies (MVB) and autophagosomal structures under ER stress conditions. A custom small-interfering RNA screen of mammalian ESCRT proteins that mediate MVB biogenesis showed that silencing of some ESCRTs, including MVB12B, inhibited unconventional CFTRΔF508 secretion. Furthermore, MVB12B overexpression partially rescued cell-surface expression and Cl channel function of CFTRΔF508. Taken together, these results suggest that components involved in early autophagosome formation and the ESCRT/MVB pathway play a key role in the stress-induced unconventional secretion of CFTR.

Original languageEnglish
Pages (from-to)1761-1778
Number of pages18
JournalAutophagy
Volume14
Issue number10
DOIs
Publication statusPublished - 2018 Oct 3

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Endosomal Sorting Complexes Required for Transport
Cystic Fibrosis Transmembrane Conductance Regulator
Autophagy
Multivesicular Bodies
Endoplasmic Reticulum Stress
Endoplasmic Reticulum
Mutation
Immunoelectron Microscopy
Secretory Pathway
Regulator Genes
Phenylalanine
Cystic Fibrosis
Small Interfering RNA
Carrier Proteins
Pharmacology

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

Cite this

Noh, Shin Hye ; Gee, Heon Yung ; Kim, Yonjung ; Piao, He ; Kim, Jiyoon ; Kang, Chung Min ; Lee, Gahyung ; Mook-Jung, Inhee ; Lee, Yangsin ; Cho, Jin Won ; Lee, Min Goo. / Specific autophagy and ESCRT components participate in the unconventional secretion of CFTR. In: Autophagy. 2018 ; Vol. 14, No. 10. pp. 1761-1778.
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title = "Specific autophagy and ESCRT components participate in the unconventional secretion of CFTR",
abstract = "The most common mutation in cystic fibrosis patients is a phenylalanine deletion at position 508 (ΔF508) in the CFTR (cystic fibrosis transmembrane conductance regulator) gene. This mutation impairs cell-surface trafficking of CFTR. During cellular stress, core-glycosylated CFTRΔF508 is transported to the cell surface from the endoplasmic reticulum (ER) via an unconventional route that bypasses the Golgi. However, the mechanisms for this unconventional secretory pathway of CFTR are not well delineated. Here, we report that components of the macroautophagy/autophagy and ESCRT (endosomal sorting complex required for transport) pathways are involved in unconventional secretion of CFTR. In mammalian cells, we found that autophagic pathways were modulated by conditions that also stimulate unconventional secretion, namely ER stress and an ER-to-Golgi transport blockade. Additionally, we found that knockdown of early autophagy components, ATG5 and ATG7, and treatment with pharmacological autophagy inhibitors, wortmannin and 3-methyladenine, abolished the unconventional secretion of CFTR that had been stimulated by ER stress and an ER-to-Golgi blockade. Interestingly, immunoelectron microscopy revealed that GORASP2/GRASP55, which mediates unconventional CFTR trafficking, is present in multivesicular bodies (MVB) and autophagosomal structures under ER stress conditions. A custom small-interfering RNA screen of mammalian ESCRT proteins that mediate MVB biogenesis showed that silencing of some ESCRTs, including MVB12B, inhibited unconventional CFTRΔF508 secretion. Furthermore, MVB12B overexpression partially rescued cell-surface expression and Cl− channel function of CFTRΔF508. Taken together, these results suggest that components involved in early autophagosome formation and the ESCRT/MVB pathway play a key role in the stress-induced unconventional secretion of CFTR.",
author = "Noh, {Shin Hye} and Gee, {Heon Yung} and Yonjung Kim and He Piao and Jiyoon Kim and Kang, {Chung Min} and Gahyung Lee and Inhee Mook-Jung and Yangsin Lee and Cho, {Jin Won} and Lee, {Min Goo}",
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Noh, SH, Gee, HY, Kim, Y, Piao, H, Kim, J, Kang, CM, Lee, G, Mook-Jung, I, Lee, Y, Cho, JW & Lee, MG 2018, 'Specific autophagy and ESCRT components participate in the unconventional secretion of CFTR', Autophagy, vol. 14, no. 10, pp. 1761-1778. https://doi.org/10.1080/15548627.2018.1489479

Specific autophagy and ESCRT components participate in the unconventional secretion of CFTR. / Noh, Shin Hye; Gee, Heon Yung; Kim, Yonjung; Piao, He; Kim, Jiyoon; Kang, Chung Min; Lee, Gahyung; Mook-Jung, Inhee; Lee, Yangsin; Cho, Jin Won; Lee, Min Goo.

In: Autophagy, Vol. 14, No. 10, 03.10.2018, p. 1761-1778.

Research output: Contribution to journalArticle

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T1 - Specific autophagy and ESCRT components participate in the unconventional secretion of CFTR

AU - Noh, Shin Hye

AU - Gee, Heon Yung

AU - Kim, Yonjung

AU - Piao, He

AU - Kim, Jiyoon

AU - Kang, Chung Min

AU - Lee, Gahyung

AU - Mook-Jung, Inhee

AU - Lee, Yangsin

AU - Cho, Jin Won

AU - Lee, Min Goo

PY - 2018/10/3

Y1 - 2018/10/3

N2 - The most common mutation in cystic fibrosis patients is a phenylalanine deletion at position 508 (ΔF508) in the CFTR (cystic fibrosis transmembrane conductance regulator) gene. This mutation impairs cell-surface trafficking of CFTR. During cellular stress, core-glycosylated CFTRΔF508 is transported to the cell surface from the endoplasmic reticulum (ER) via an unconventional route that bypasses the Golgi. However, the mechanisms for this unconventional secretory pathway of CFTR are not well delineated. Here, we report that components of the macroautophagy/autophagy and ESCRT (endosomal sorting complex required for transport) pathways are involved in unconventional secretion of CFTR. In mammalian cells, we found that autophagic pathways were modulated by conditions that also stimulate unconventional secretion, namely ER stress and an ER-to-Golgi transport blockade. Additionally, we found that knockdown of early autophagy components, ATG5 and ATG7, and treatment with pharmacological autophagy inhibitors, wortmannin and 3-methyladenine, abolished the unconventional secretion of CFTR that had been stimulated by ER stress and an ER-to-Golgi blockade. Interestingly, immunoelectron microscopy revealed that GORASP2/GRASP55, which mediates unconventional CFTR trafficking, is present in multivesicular bodies (MVB) and autophagosomal structures under ER stress conditions. A custom small-interfering RNA screen of mammalian ESCRT proteins that mediate MVB biogenesis showed that silencing of some ESCRTs, including MVB12B, inhibited unconventional CFTRΔF508 secretion. Furthermore, MVB12B overexpression partially rescued cell-surface expression and Cl− channel function of CFTRΔF508. Taken together, these results suggest that components involved in early autophagosome formation and the ESCRT/MVB pathway play a key role in the stress-induced unconventional secretion of CFTR.

AB - The most common mutation in cystic fibrosis patients is a phenylalanine deletion at position 508 (ΔF508) in the CFTR (cystic fibrosis transmembrane conductance regulator) gene. This mutation impairs cell-surface trafficking of CFTR. During cellular stress, core-glycosylated CFTRΔF508 is transported to the cell surface from the endoplasmic reticulum (ER) via an unconventional route that bypasses the Golgi. However, the mechanisms for this unconventional secretory pathway of CFTR are not well delineated. Here, we report that components of the macroautophagy/autophagy and ESCRT (endosomal sorting complex required for transport) pathways are involved in unconventional secretion of CFTR. In mammalian cells, we found that autophagic pathways were modulated by conditions that also stimulate unconventional secretion, namely ER stress and an ER-to-Golgi transport blockade. Additionally, we found that knockdown of early autophagy components, ATG5 and ATG7, and treatment with pharmacological autophagy inhibitors, wortmannin and 3-methyladenine, abolished the unconventional secretion of CFTR that had been stimulated by ER stress and an ER-to-Golgi blockade. Interestingly, immunoelectron microscopy revealed that GORASP2/GRASP55, which mediates unconventional CFTR trafficking, is present in multivesicular bodies (MVB) and autophagosomal structures under ER stress conditions. A custom small-interfering RNA screen of mammalian ESCRT proteins that mediate MVB biogenesis showed that silencing of some ESCRTs, including MVB12B, inhibited unconventional CFTRΔF508 secretion. Furthermore, MVB12B overexpression partially rescued cell-surface expression and Cl− channel function of CFTRΔF508. Taken together, these results suggest that components involved in early autophagosome formation and the ESCRT/MVB pathway play a key role in the stress-induced unconventional secretion of CFTR.

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