Structural and biophysical characterization of the cytoplasmic domains of human BAP29 and BAP31

Two members of the B-cell associated 31 (BAP31) family are found in humans; BAP29 and BAP31. These are ubiquitously expressed receptors residing in the endoplasmic reticulum. BAP31 functions in sorting of membrane proteins and in caspase-8 mediated apoptosis, while BAP29 appears to mainly corroborat...

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Main Authors: Löw, Christian, Moberg, Per, Guettou, Fatma, Maddi, Karthik, Nordlund, Pär, Quistgaard, Esben M.
Other Authors: School of Biological Sciences
Format: Article
Language:English
Published: 2013
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Online Access:https://hdl.handle.net/10356/98129
http://hdl.handle.net/10220/13322
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spelling sg-ntu-dr.10356-981292023-02-28T16:56:19Z Structural and biophysical characterization of the cytoplasmic domains of human BAP29 and BAP31 Löw, Christian Moberg, Per Guettou, Fatma Maddi, Karthik Nordlund, Pär Quistgaard, Esben M. School of Biological Sciences DRNTU::Science::Biological sciences Two members of the B-cell associated 31 (BAP31) family are found in humans; BAP29 and BAP31. These are ubiquitously expressed receptors residing in the endoplasmic reticulum. BAP31 functions in sorting of membrane proteins and in caspase-8 mediated apoptosis, while BAP29 appears to mainly corroborate with BAP31 in sorting. The N-terminal half of these proteins is membrane-bound while the C-terminal half is cytoplasmic. The latter include the so called variant of death effector domain (vDED), which shares weak sequence homology with DED domains. Here we present two structures of BAP31 vDED determined from a single and a twinned crystal, grown at pH 8.0 and pH 4.2, respectively. These structures show that BAP31 vDED forms a dimeric parallel coiled coil with no structural similarity to DED domains. Solution studies support this conclusion and strongly suggest that an additional α-helical domain is present in the C-terminal cytoplasmic region, probably forming a second coiled coil. The thermal stability of BAP31 vDED is quite modest at neutral pH, suggesting that it may assemble in a dynamic fashion in vivo. Surprisingly, BAP29 vDED is partially unfolded at pH 7, while a coiled coil is formed at pH 4.2 in vitro. It is however likely that folding of the domain is triggered by other factors than low pH in vivo. We found no evidence for direct interaction of the cytoplasmic domains of BAP29 and BAP31. Published version 2013-09-04T08:30:01Z 2019-12-06T19:51:01Z 2013-09-04T08:30:01Z 2019-12-06T19:51:01Z 2013 2013 Journal Article Quistgaard, E. M., Löw, C., Moberg, P., Guettou, F., Maddi, K.,& Nordlund, P. (2013). Structural and Biophysical Characterization of the Cytoplasmic Domains of Human BAP29 and BAP31. PLoS ONE, 8(8), e71111. 1932-6203 https://hdl.handle.net/10356/98129 http://hdl.handle.net/10220/13322 10.1371/journal.pone.0071111 23967155 en PLoS ONE © 2013 Quistgaard et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Science::Biological sciences
spellingShingle DRNTU::Science::Biological sciences
Löw, Christian
Moberg, Per
Guettou, Fatma
Maddi, Karthik
Nordlund, Pär
Quistgaard, Esben M.
Structural and biophysical characterization of the cytoplasmic domains of human BAP29 and BAP31
description Two members of the B-cell associated 31 (BAP31) family are found in humans; BAP29 and BAP31. These are ubiquitously expressed receptors residing in the endoplasmic reticulum. BAP31 functions in sorting of membrane proteins and in caspase-8 mediated apoptosis, while BAP29 appears to mainly corroborate with BAP31 in sorting. The N-terminal half of these proteins is membrane-bound while the C-terminal half is cytoplasmic. The latter include the so called variant of death effector domain (vDED), which shares weak sequence homology with DED domains. Here we present two structures of BAP31 vDED determined from a single and a twinned crystal, grown at pH 8.0 and pH 4.2, respectively. These structures show that BAP31 vDED forms a dimeric parallel coiled coil with no structural similarity to DED domains. Solution studies support this conclusion and strongly suggest that an additional α-helical domain is present in the C-terminal cytoplasmic region, probably forming a second coiled coil. The thermal stability of BAP31 vDED is quite modest at neutral pH, suggesting that it may assemble in a dynamic fashion in vivo. Surprisingly, BAP29 vDED is partially unfolded at pH 7, while a coiled coil is formed at pH 4.2 in vitro. It is however likely that folding of the domain is triggered by other factors than low pH in vivo. We found no evidence for direct interaction of the cytoplasmic domains of BAP29 and BAP31.
author2 School of Biological Sciences
author_facet School of Biological Sciences
Löw, Christian
Moberg, Per
Guettou, Fatma
Maddi, Karthik
Nordlund, Pär
Quistgaard, Esben M.
format Article
author Löw, Christian
Moberg, Per
Guettou, Fatma
Maddi, Karthik
Nordlund, Pär
Quistgaard, Esben M.
author_sort Löw, Christian
title Structural and biophysical characterization of the cytoplasmic domains of human BAP29 and BAP31
title_short Structural and biophysical characterization of the cytoplasmic domains of human BAP29 and BAP31
title_full Structural and biophysical characterization of the cytoplasmic domains of human BAP29 and BAP31
title_fullStr Structural and biophysical characterization of the cytoplasmic domains of human BAP29 and BAP31
title_full_unstemmed Structural and biophysical characterization of the cytoplasmic domains of human BAP29 and BAP31
title_sort structural and biophysical characterization of the cytoplasmic domains of human bap29 and bap31
publishDate 2013
url https://hdl.handle.net/10356/98129
http://hdl.handle.net/10220/13322
_version_ 1759857461788934144