Mammalian ECD protein is a novel negative regulator of the PERK arm of the unfolded protein response

Appolinaire A. Olou, Aniruddha Sarkar, Aditya Bele, Channabasavaiah B Gurumurthy, Riyaz A. Mir, Shalis A. Ammons, Sameer Mirza, Irfana Saleem, Fumihiko Urano, Hamid Band, Vimla Band

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Mammalian Ecdysoneless (ECD) is a highly conserved ortholog of the Drosophila Ecd gene product whose mutations impair the synthesis of Ecdysone and produce cell-autonomous survival defects, but the mechanisms by which ECD functions are largely unknown. Here we present evidence that ECD regulates the endoplasmic reticulum (ER) stress response. ER stress induction led to a reduced ECD protein level, but this effect was not seen in PKR-like ER kinase knockout (PERK-KO) or phosphodeficient eukaryotic translation initiation factor 2α (eIF2α) mouse embryonic fibroblasts (MEFs); moreover, ECD mRNA levels were increased, suggesting impaired ECD translation as the mechanism for reduced protein levels. ECD colocalizes and coimmunoprecipitates with PERK and GRP78. ECD depletion increased the levels of both phospho-PERK (p-PERK) and p-eIF2α, and these effects were enhanced upon ER stress induction. Reciprocally, overexpression of ECD led to marked decreases in p-PERK, p-eIF2α, and ATF4 levels but robust increases in GRP78 protein levels. However, GRP78 mRNA levels were unchanged, suggesting a posttranscriptional event. Knockdown of GRP78 reversed the attenuating effect of ECD overexpression on PERK signaling. Significantly, overexpression of ECD provided a survival advantage to cells upon ER stress induction. Taken together, our data demonstrate that ECD promotes survival upon ER stress by increasing GRP78 protein levels to enhance the adaptive folding protein in the ER to attenuate PERK signaling.

Original languageEnglish (US)
Article numbere00030-17
JournalMolecular and cellular biology
Volume37
Issue number18
DOIs
StatePublished - Sep 1 2017

Fingerprint

Unfolded Protein Response
Endoplasmic Reticulum Stress
Eukaryotic Initiation Factor-2
Eukaryotic Initiation Factors
Proteins
Endoplasmic Reticulum
Ecdysone
Messenger RNA
Protein Folding
Drosophila
Cell Survival
Phosphotransferases
Fibroblasts
Mutation
Genes

Keywords

  • Cell survival
  • ECD
  • ER
  • GRP78
  • PERK
  • UPR

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

Cite this

Mammalian ECD protein is a novel negative regulator of the PERK arm of the unfolded protein response. / Olou, Appolinaire A.; Sarkar, Aniruddha; Bele, Aditya; Gurumurthy, Channabasavaiah B; Mir, Riyaz A.; Ammons, Shalis A.; Mirza, Sameer; Saleem, Irfana; Urano, Fumihiko; Band, Hamid; Band, Vimla.

In: Molecular and cellular biology, Vol. 37, No. 18, e00030-17, 01.09.2017.

Research output: Contribution to journalArticle

Olou, Appolinaire A. ; Sarkar, Aniruddha ; Bele, Aditya ; Gurumurthy, Channabasavaiah B ; Mir, Riyaz A. ; Ammons, Shalis A. ; Mirza, Sameer ; Saleem, Irfana ; Urano, Fumihiko ; Band, Hamid ; Band, Vimla. / Mammalian ECD protein is a novel negative regulator of the PERK arm of the unfolded protein response. In: Molecular and cellular biology. 2017 ; Vol. 37, No. 18.
@article{b748117ffac94a90a5acbd03e9737513,
title = "Mammalian ECD protein is a novel negative regulator of the PERK arm of the unfolded protein response",
abstract = "Mammalian Ecdysoneless (ECD) is a highly conserved ortholog of the Drosophila Ecd gene product whose mutations impair the synthesis of Ecdysone and produce cell-autonomous survival defects, but the mechanisms by which ECD functions are largely unknown. Here we present evidence that ECD regulates the endoplasmic reticulum (ER) stress response. ER stress induction led to a reduced ECD protein level, but this effect was not seen in PKR-like ER kinase knockout (PERK-KO) or phosphodeficient eukaryotic translation initiation factor 2α (eIF2α) mouse embryonic fibroblasts (MEFs); moreover, ECD mRNA levels were increased, suggesting impaired ECD translation as the mechanism for reduced protein levels. ECD colocalizes and coimmunoprecipitates with PERK and GRP78. ECD depletion increased the levels of both phospho-PERK (p-PERK) and p-eIF2α, and these effects were enhanced upon ER stress induction. Reciprocally, overexpression of ECD led to marked decreases in p-PERK, p-eIF2α, and ATF4 levels but robust increases in GRP78 protein levels. However, GRP78 mRNA levels were unchanged, suggesting a posttranscriptional event. Knockdown of GRP78 reversed the attenuating effect of ECD overexpression on PERK signaling. Significantly, overexpression of ECD provided a survival advantage to cells upon ER stress induction. Taken together, our data demonstrate that ECD promotes survival upon ER stress by increasing GRP78 protein levels to enhance the adaptive folding protein in the ER to attenuate PERK signaling.",
keywords = "Cell survival, ECD, ER, GRP78, PERK, UPR",
author = "Olou, {Appolinaire A.} and Aniruddha Sarkar and Aditya Bele and Gurumurthy, {Channabasavaiah B} and Mir, {Riyaz A.} and Ammons, {Shalis A.} and Sameer Mirza and Irfana Saleem and Fumihiko Urano and Hamid Band and Vimla Band",
year = "2017",
month = "9",
day = "1",
doi = "10.1128/MCB.00030-17",
language = "English (US)",
volume = "37",
journal = "Molecular and Cellular Biology",
issn = "0270-7306",
publisher = "American Society for Microbiology",
number = "18",

}

TY - JOUR

T1 - Mammalian ECD protein is a novel negative regulator of the PERK arm of the unfolded protein response

AU - Olou, Appolinaire A.

AU - Sarkar, Aniruddha

AU - Bele, Aditya

AU - Gurumurthy, Channabasavaiah B

AU - Mir, Riyaz A.

AU - Ammons, Shalis A.

AU - Mirza, Sameer

AU - Saleem, Irfana

AU - Urano, Fumihiko

AU - Band, Hamid

AU - Band, Vimla

PY - 2017/9/1

Y1 - 2017/9/1

N2 - Mammalian Ecdysoneless (ECD) is a highly conserved ortholog of the Drosophila Ecd gene product whose mutations impair the synthesis of Ecdysone and produce cell-autonomous survival defects, but the mechanisms by which ECD functions are largely unknown. Here we present evidence that ECD regulates the endoplasmic reticulum (ER) stress response. ER stress induction led to a reduced ECD protein level, but this effect was not seen in PKR-like ER kinase knockout (PERK-KO) or phosphodeficient eukaryotic translation initiation factor 2α (eIF2α) mouse embryonic fibroblasts (MEFs); moreover, ECD mRNA levels were increased, suggesting impaired ECD translation as the mechanism for reduced protein levels. ECD colocalizes and coimmunoprecipitates with PERK and GRP78. ECD depletion increased the levels of both phospho-PERK (p-PERK) and p-eIF2α, and these effects were enhanced upon ER stress induction. Reciprocally, overexpression of ECD led to marked decreases in p-PERK, p-eIF2α, and ATF4 levels but robust increases in GRP78 protein levels. However, GRP78 mRNA levels were unchanged, suggesting a posttranscriptional event. Knockdown of GRP78 reversed the attenuating effect of ECD overexpression on PERK signaling. Significantly, overexpression of ECD provided a survival advantage to cells upon ER stress induction. Taken together, our data demonstrate that ECD promotes survival upon ER stress by increasing GRP78 protein levels to enhance the adaptive folding protein in the ER to attenuate PERK signaling.

AB - Mammalian Ecdysoneless (ECD) is a highly conserved ortholog of the Drosophila Ecd gene product whose mutations impair the synthesis of Ecdysone and produce cell-autonomous survival defects, but the mechanisms by which ECD functions are largely unknown. Here we present evidence that ECD regulates the endoplasmic reticulum (ER) stress response. ER stress induction led to a reduced ECD protein level, but this effect was not seen in PKR-like ER kinase knockout (PERK-KO) or phosphodeficient eukaryotic translation initiation factor 2α (eIF2α) mouse embryonic fibroblasts (MEFs); moreover, ECD mRNA levels were increased, suggesting impaired ECD translation as the mechanism for reduced protein levels. ECD colocalizes and coimmunoprecipitates with PERK and GRP78. ECD depletion increased the levels of both phospho-PERK (p-PERK) and p-eIF2α, and these effects were enhanced upon ER stress induction. Reciprocally, overexpression of ECD led to marked decreases in p-PERK, p-eIF2α, and ATF4 levels but robust increases in GRP78 protein levels. However, GRP78 mRNA levels were unchanged, suggesting a posttranscriptional event. Knockdown of GRP78 reversed the attenuating effect of ECD overexpression on PERK signaling. Significantly, overexpression of ECD provided a survival advantage to cells upon ER stress induction. Taken together, our data demonstrate that ECD promotes survival upon ER stress by increasing GRP78 protein levels to enhance the adaptive folding protein in the ER to attenuate PERK signaling.

KW - Cell survival

KW - ECD

KW - ER

KW - GRP78

KW - PERK

KW - UPR

UR - http://www.scopus.com/inward/record.url?scp=85028363863&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85028363863&partnerID=8YFLogxK

U2 - 10.1128/MCB.00030-17

DO - 10.1128/MCB.00030-17

M3 - Article

C2 - 28652267

AN - SCOPUS:85028363863

VL - 37

JO - Molecular and Cellular Biology

JF - Molecular and Cellular Biology

SN - 0270-7306

IS - 18

M1 - e00030-17

ER -