Stable binding of ATF6 to BiP in the endoplasmic reticulum stress response

Jingshi Shen, Erik L. Snapp, Jennifer Lippincott-Schwartz, Ron Prywes

Research output: Contribution to journalArticle

149 Citations (Scopus)

Abstract

Endoplasmic reticulum (ER) stress-induced activation of ATF6, an ER membrane-bound transcription factor, requires a dissociation step from its inhibitory regulator, BiP. It has been generally postulated that dissociation of the BiP-ATF6 complex is a result of the competitive binding of misfolded proteins generated during ER stress. Here we present evidence against this model and for an active regulatory mechanism for dissociation of the complex. Contradictory to the competition model that is based on dynamic binding of BiP to ATF6, our data reveal relatively stable binding. First, the complex was easily isolated, in contrast to many chaperone complexes that require chemical cross-linking. Second, ATF6 bound at similar levels to wild-type BiP and a BiP mutant form that binds substrates stably because of a defect in its ATPase activity. Third, ER stress specifically induced the dissociation of BiP from ER stress transducers while the competition model would predict dissociation from any specific substrate. Fourth, the ATF6-BiP complex was resistant to ATP-induced dissociation in vitro when isolated without detergents, suggesting that cofactors stabilize the complex. In favor of an active dissociation model, one specific region within the ATF6 lumenal domain was identified as a specific ER stress-responsive sequence required for ER stress-triggered BiP release. Together, our results do not support a model in which competitive binding of misfolded proteins causes dissociation of the BiP-ATF6 complex in stressed cells. We propose that stable BiP binding is essential for ATF6 regulation and that ER stress dissociates BiP from ATF6 by actively restarting the BiP ATPase cycle.

Original languageEnglish (US)
Pages (from-to)921-932
Number of pages12
JournalMolecular and Cellular Biology
Volume25
Issue number3
DOIs
StatePublished - Feb 2005
Externally publishedYes

Fingerprint

Endoplasmic Reticulum Stress
Competitive Binding
Adenosine Triphosphatases
Carrier Proteins
Transducers
Endoplasmic Reticulum
Detergents
Transcription Factors
Adenosine Triphosphate
Membranes

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cell Biology

Cite this

Stable binding of ATF6 to BiP in the endoplasmic reticulum stress response. / Shen, Jingshi; Snapp, Erik L.; Lippincott-Schwartz, Jennifer; Prywes, Ron.

In: Molecular and Cellular Biology, Vol. 25, No. 3, 02.2005, p. 921-932.

Research output: Contribution to journalArticle

Shen, Jingshi ; Snapp, Erik L. ; Lippincott-Schwartz, Jennifer ; Prywes, Ron. / Stable binding of ATF6 to BiP in the endoplasmic reticulum stress response. In: Molecular and Cellular Biology. 2005 ; Vol. 25, No. 3. pp. 921-932.
@article{d10a180654944f4e97845ae02eb19b6b,
title = "Stable binding of ATF6 to BiP in the endoplasmic reticulum stress response",
abstract = "Endoplasmic reticulum (ER) stress-induced activation of ATF6, an ER membrane-bound transcription factor, requires a dissociation step from its inhibitory regulator, BiP. It has been generally postulated that dissociation of the BiP-ATF6 complex is a result of the competitive binding of misfolded proteins generated during ER stress. Here we present evidence against this model and for an active regulatory mechanism for dissociation of the complex. Contradictory to the competition model that is based on dynamic binding of BiP to ATF6, our data reveal relatively stable binding. First, the complex was easily isolated, in contrast to many chaperone complexes that require chemical cross-linking. Second, ATF6 bound at similar levels to wild-type BiP and a BiP mutant form that binds substrates stably because of a defect in its ATPase activity. Third, ER stress specifically induced the dissociation of BiP from ER stress transducers while the competition model would predict dissociation from any specific substrate. Fourth, the ATF6-BiP complex was resistant to ATP-induced dissociation in vitro when isolated without detergents, suggesting that cofactors stabilize the complex. In favor of an active dissociation model, one specific region within the ATF6 lumenal domain was identified as a specific ER stress-responsive sequence required for ER stress-triggered BiP release. Together, our results do not support a model in which competitive binding of misfolded proteins causes dissociation of the BiP-ATF6 complex in stressed cells. We propose that stable BiP binding is essential for ATF6 regulation and that ER stress dissociates BiP from ATF6 by actively restarting the BiP ATPase cycle.",
author = "Jingshi Shen and Snapp, {Erik L.} and Jennifer Lippincott-Schwartz and Ron Prywes",
year = "2005",
month = "2",
doi = "10.1128/MCB.25.3.921-932.2005",
language = "English (US)",
volume = "25",
pages = "921--932",
journal = "Molecular and Cellular Biology",
issn = "0270-7306",
publisher = "American Society for Microbiology",
number = "3",

}

TY - JOUR

T1 - Stable binding of ATF6 to BiP in the endoplasmic reticulum stress response

AU - Shen, Jingshi

AU - Snapp, Erik L.

AU - Lippincott-Schwartz, Jennifer

AU - Prywes, Ron

PY - 2005/2

Y1 - 2005/2

N2 - Endoplasmic reticulum (ER) stress-induced activation of ATF6, an ER membrane-bound transcription factor, requires a dissociation step from its inhibitory regulator, BiP. It has been generally postulated that dissociation of the BiP-ATF6 complex is a result of the competitive binding of misfolded proteins generated during ER stress. Here we present evidence against this model and for an active regulatory mechanism for dissociation of the complex. Contradictory to the competition model that is based on dynamic binding of BiP to ATF6, our data reveal relatively stable binding. First, the complex was easily isolated, in contrast to many chaperone complexes that require chemical cross-linking. Second, ATF6 bound at similar levels to wild-type BiP and a BiP mutant form that binds substrates stably because of a defect in its ATPase activity. Third, ER stress specifically induced the dissociation of BiP from ER stress transducers while the competition model would predict dissociation from any specific substrate. Fourth, the ATF6-BiP complex was resistant to ATP-induced dissociation in vitro when isolated without detergents, suggesting that cofactors stabilize the complex. In favor of an active dissociation model, one specific region within the ATF6 lumenal domain was identified as a specific ER stress-responsive sequence required for ER stress-triggered BiP release. Together, our results do not support a model in which competitive binding of misfolded proteins causes dissociation of the BiP-ATF6 complex in stressed cells. We propose that stable BiP binding is essential for ATF6 regulation and that ER stress dissociates BiP from ATF6 by actively restarting the BiP ATPase cycle.

AB - Endoplasmic reticulum (ER) stress-induced activation of ATF6, an ER membrane-bound transcription factor, requires a dissociation step from its inhibitory regulator, BiP. It has been generally postulated that dissociation of the BiP-ATF6 complex is a result of the competitive binding of misfolded proteins generated during ER stress. Here we present evidence against this model and for an active regulatory mechanism for dissociation of the complex. Contradictory to the competition model that is based on dynamic binding of BiP to ATF6, our data reveal relatively stable binding. First, the complex was easily isolated, in contrast to many chaperone complexes that require chemical cross-linking. Second, ATF6 bound at similar levels to wild-type BiP and a BiP mutant form that binds substrates stably because of a defect in its ATPase activity. Third, ER stress specifically induced the dissociation of BiP from ER stress transducers while the competition model would predict dissociation from any specific substrate. Fourth, the ATF6-BiP complex was resistant to ATP-induced dissociation in vitro when isolated without detergents, suggesting that cofactors stabilize the complex. In favor of an active dissociation model, one specific region within the ATF6 lumenal domain was identified as a specific ER stress-responsive sequence required for ER stress-triggered BiP release. Together, our results do not support a model in which competitive binding of misfolded proteins causes dissociation of the BiP-ATF6 complex in stressed cells. We propose that stable BiP binding is essential for ATF6 regulation and that ER stress dissociates BiP from ATF6 by actively restarting the BiP ATPase cycle.

UR - http://www.scopus.com/inward/record.url?scp=12844257546&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=12844257546&partnerID=8YFLogxK

U2 - 10.1128/MCB.25.3.921-932.2005

DO - 10.1128/MCB.25.3.921-932.2005

M3 - Article

VL - 25

SP - 921

EP - 932

JO - Molecular and Cellular Biology

JF - Molecular and Cellular Biology

SN - 0270-7306

IS - 3

ER -