Cargando…

The 2β Splice Variation Alters the Structure and Function of the Stromal Interaction Molecule Coiled-Coil Domains

Stromal interaction molecule (STIM)-1 and -2 regulate agonist-induced and basal cytosolic calcium (Ca(2+)) levels after oligomerization and translocation to endoplasmic reticulum (ER)-plasma membrane (PM) junctions. At these junctions, the STIM cytosolic coiled-coil (CC) domains couple to PM Orai1 p...

Descripción completa

Detalles Bibliográficos
Autores principales: Chung, Steve, Zhang, MengQi, Stathopulos, Peter B.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6274866/
https://www.ncbi.nlm.nih.gov/pubmed/30366379
http://dx.doi.org/10.3390/ijms19113316
_version_ 1783377706863296512
author Chung, Steve
Zhang, MengQi
Stathopulos, Peter B.
author_facet Chung, Steve
Zhang, MengQi
Stathopulos, Peter B.
author_sort Chung, Steve
collection PubMed
description Stromal interaction molecule (STIM)-1 and -2 regulate agonist-induced and basal cytosolic calcium (Ca(2+)) levels after oligomerization and translocation to endoplasmic reticulum (ER)-plasma membrane (PM) junctions. At these junctions, the STIM cytosolic coiled-coil (CC) domains couple to PM Orai1 proteins and gate these Ca(2+) release-activated Ca(2+) (CRAC) channels, which facilitate store-operated Ca(2+) entry (SOCE). Unlike STIM1 and STIM2, which are SOCE activators, the STIM2β splice variant contains an 8-residue insert located within the conserved CCs which inhibits SOCE. It remains unclear if the 2β insert further depotentiates weak STIM2 coupling to Orai1 or independently causes structural perturbations which prevent SOCE. Here, we use far-UV circular dichroism, light scattering, exposed hydrophobicity analysis, solution small angle X-ray scattering, and a chimeric STIM1/STIM2β functional assessment to provide insights into the molecular mechanism by which the 2β insert precludes SOCE activation. We find that the 2β insert reduces the overall α-helicity and enhances the exposed hydrophobicity of the STIM2 CC domains in the absence of a global conformational change. Remarkably, incorporation of the 2β insert into the STIM1 context not only affects the secondary structure and hydrophobicity as observed for STIM2, but also eliminates the more robust SOCE response mediated by STIM1. Collectively, our data show that the 2β insert directly precludes Orai1 channel activation by inducing structural perturbations in the STIM CC region.
format Online
Article
Text
id pubmed-6274866
institution National Center for Biotechnology Information
language English
publishDate 2018
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-62748662018-12-15 The 2β Splice Variation Alters the Structure and Function of the Stromal Interaction Molecule Coiled-Coil Domains Chung, Steve Zhang, MengQi Stathopulos, Peter B. Int J Mol Sci Article Stromal interaction molecule (STIM)-1 and -2 regulate agonist-induced and basal cytosolic calcium (Ca(2+)) levels after oligomerization and translocation to endoplasmic reticulum (ER)-plasma membrane (PM) junctions. At these junctions, the STIM cytosolic coiled-coil (CC) domains couple to PM Orai1 proteins and gate these Ca(2+) release-activated Ca(2+) (CRAC) channels, which facilitate store-operated Ca(2+) entry (SOCE). Unlike STIM1 and STIM2, which are SOCE activators, the STIM2β splice variant contains an 8-residue insert located within the conserved CCs which inhibits SOCE. It remains unclear if the 2β insert further depotentiates weak STIM2 coupling to Orai1 or independently causes structural perturbations which prevent SOCE. Here, we use far-UV circular dichroism, light scattering, exposed hydrophobicity analysis, solution small angle X-ray scattering, and a chimeric STIM1/STIM2β functional assessment to provide insights into the molecular mechanism by which the 2β insert precludes SOCE activation. We find that the 2β insert reduces the overall α-helicity and enhances the exposed hydrophobicity of the STIM2 CC domains in the absence of a global conformational change. Remarkably, incorporation of the 2β insert into the STIM1 context not only affects the secondary structure and hydrophobicity as observed for STIM2, but also eliminates the more robust SOCE response mediated by STIM1. Collectively, our data show that the 2β insert directly precludes Orai1 channel activation by inducing structural perturbations in the STIM CC region. MDPI 2018-10-25 /pmc/articles/PMC6274866/ /pubmed/30366379 http://dx.doi.org/10.3390/ijms19113316 Text en © 2018 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
Chung, Steve
Zhang, MengQi
Stathopulos, Peter B.
The 2β Splice Variation Alters the Structure and Function of the Stromal Interaction Molecule Coiled-Coil Domains
title The 2β Splice Variation Alters the Structure and Function of the Stromal Interaction Molecule Coiled-Coil Domains
title_full The 2β Splice Variation Alters the Structure and Function of the Stromal Interaction Molecule Coiled-Coil Domains
title_fullStr The 2β Splice Variation Alters the Structure and Function of the Stromal Interaction Molecule Coiled-Coil Domains
title_full_unstemmed The 2β Splice Variation Alters the Structure and Function of the Stromal Interaction Molecule Coiled-Coil Domains
title_short The 2β Splice Variation Alters the Structure and Function of the Stromal Interaction Molecule Coiled-Coil Domains
title_sort 2β splice variation alters the structure and function of the stromal interaction molecule coiled-coil domains
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6274866/
https://www.ncbi.nlm.nih.gov/pubmed/30366379
http://dx.doi.org/10.3390/ijms19113316
work_keys_str_mv AT chungsteve the2bsplicevariationaltersthestructureandfunctionofthestromalinteractionmoleculecoiledcoildomains
AT zhangmengqi the2bsplicevariationaltersthestructureandfunctionofthestromalinteractionmoleculecoiledcoildomains
AT stathopulospeterb the2bsplicevariationaltersthestructureandfunctionofthestromalinteractionmoleculecoiledcoildomains
AT chungsteve 2bsplicevariationaltersthestructureandfunctionofthestromalinteractionmoleculecoiledcoildomains
AT zhangmengqi 2bsplicevariationaltersthestructureandfunctionofthestromalinteractionmoleculecoiledcoildomains
AT stathopulospeterb 2bsplicevariationaltersthestructureandfunctionofthestromalinteractionmoleculecoiledcoildomains