Human junctophilin-2 undergoes a structural rearrangement upon binding PtdIns(3,4,5)P3 and the S101R mutation identified in hypertrophic cardiomyopathy obviates this response

JP2 (junctophilin-2) is believed to hold the transverse tubular and jSR (junctional sarcoplasmic reticulum) membranes in a precise geometry that facilitates excitation–contraction coupling in cardiomyocytes. We have expressed and purified human JP2 and shown using electron microscopy that the protei...

Full description

Bibliographic Details
Main Authors:	Bennett, Hayley J., Davenport, John Bernard, Collins, Richard F., Trafford, Andrew W., Pinali, Christian, Kitmitto, Ashraf
Format:	Online
Language:	English
Published:	Portland Press Ltd. 2013
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3898329/

id	pubmed-3898329
recordtype	oai_dc
spelling	pubmed-38983292014-01-23 Human junctophilin-2 undergoes a structural rearrangement upon binding PtdIns(3,4,5)P3 and the S101R mutation identified in hypertrophic cardiomyopathy obviates this response Bennett, Hayley J. Davenport, John Bernard Collins, Richard F. Trafford, Andrew W. Pinali, Christian Kitmitto, Ashraf Research Article JP2 (junctophilin-2) is believed to hold the transverse tubular and jSR (junctional sarcoplasmic reticulum) membranes in a precise geometry that facilitates excitation–contraction coupling in cardiomyocytes. We have expressed and purified human JP2 and shown using electron microscopy that the protein forms elongated structures ~15 nm long and 2 nm wide. Employing lipid-binding assays and quartz crystal microbalance with dissipation we have determined that JP2 is selective for PS (phosphatidylserine), with a Kd value of ~0.5 μM, with the N-terminal domain mediating this interaction. JP2 also binds PtdIns(3,4,5)P3 at a different site than PS, resulting in the protein adopting a more flexible conformation; this interaction is modulated by both Ca2+ and Mg2+ ions. We show that the S101R mutation identified in patients with hypertrophic cardiomyopathy leads to modification of the protein secondary structure, forming a more flexible molecule with an increased affinity for PS, but does not undergo a structural transition in response to binding PtdIns(3,4,5)P3. In conclusion, the present study provides new insights into the structural and lipid-binding properties of JP2 and how the S101R mutation may have an effect upon the stability of the dyad organization with the potential to alter JP2–protein interactions regulating Ca2+ cycling. Portland Press Ltd. 2013-11-08 2013-12-01 /pmc/articles/PMC3898329/ /pubmed/24001019 http://dx.doi.org/10.1042/BJ20130591 Text en © 2013 The author(s) has paid for this article to be freely available under the terms of the Creative Commons Attribution Licence (CC-BY)(http://creativecommons.org/licenses/by/3.0/) which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. http://creativecommons.org/licenses/by/3.0/ 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 work is properly cited.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Bennett, Hayley J. Davenport, John Bernard Collins, Richard F. Trafford, Andrew W. Pinali, Christian Kitmitto, Ashraf
spellingShingle	Bennett, Hayley J. Davenport, John Bernard Collins, Richard F. Trafford, Andrew W. Pinali, Christian Kitmitto, Ashraf Human junctophilin-2 undergoes a structural rearrangement upon binding PtdIns(3,4,5)P3 and the S101R mutation identified in hypertrophic cardiomyopathy obviates this response
author_facet	Bennett, Hayley J. Davenport, John Bernard Collins, Richard F. Trafford, Andrew W. Pinali, Christian Kitmitto, Ashraf
author_sort	Bennett, Hayley J.
title	Human junctophilin-2 undergoes a structural rearrangement upon binding PtdIns(3,4,5)P3 and the S101R mutation identified in hypertrophic cardiomyopathy obviates this response
title_short	Human junctophilin-2 undergoes a structural rearrangement upon binding PtdIns(3,4,5)P3 and the S101R mutation identified in hypertrophic cardiomyopathy obviates this response
title_full	Human junctophilin-2 undergoes a structural rearrangement upon binding PtdIns(3,4,5)P3 and the S101R mutation identified in hypertrophic cardiomyopathy obviates this response
title_fullStr	Human junctophilin-2 undergoes a structural rearrangement upon binding PtdIns(3,4,5)P3 and the S101R mutation identified in hypertrophic cardiomyopathy obviates this response
title_full_unstemmed	Human junctophilin-2 undergoes a structural rearrangement upon binding PtdIns(3,4,5)P3 and the S101R mutation identified in hypertrophic cardiomyopathy obviates this response
title_sort	human junctophilin-2 undergoes a structural rearrangement upon binding ptdins(3,4,5)p3 and the s101r mutation identified in hypertrophic cardiomyopathy obviates this response
description	JP2 (junctophilin-2) is believed to hold the transverse tubular and jSR (junctional sarcoplasmic reticulum) membranes in a precise geometry that facilitates excitation–contraction coupling in cardiomyocytes. We have expressed and purified human JP2 and shown using electron microscopy that the protein forms elongated structures ~15 nm long and 2 nm wide. Employing lipid-binding assays and quartz crystal microbalance with dissipation we have determined that JP2 is selective for PS (phosphatidylserine), with a Kd value of ~0.5 μM, with the N-terminal domain mediating this interaction. JP2 also binds PtdIns(3,4,5)P3 at a different site than PS, resulting in the protein adopting a more flexible conformation; this interaction is modulated by both Ca2+ and Mg2+ ions. We show that the S101R mutation identified in patients with hypertrophic cardiomyopathy leads to modification of the protein secondary structure, forming a more flexible molecule with an increased affinity for PS, but does not undergo a structural transition in response to binding PtdIns(3,4,5)P3. In conclusion, the present study provides new insights into the structural and lipid-binding properties of JP2 and how the S101R mutation may have an effect upon the stability of the dyad organization with the potential to alter JP2–protein interactions regulating Ca2+ cycling.
publisher	Portland Press Ltd.
publishDate	2013
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3898329/
_version_	1612049927540572160

Human junctophilin-2 undergoes a structural rearrangement upon binding PtdIns(3,4,5)P3 and the S101R mutation identified in hypertrophic cardiomyopathy obviates this response

Similar Items