The University of Southampton
University of Southampton Institutional Repository

Phospholamban and sarcolipin are maintained in the endoplasmic reticulum by retrieval from the ER-Golgi intermediate compartment

Phospholamban and sarcolipin are maintained in the endoplasmic reticulum by retrieval from the ER-Golgi intermediate compartment
Phospholamban and sarcolipin are maintained in the endoplasmic reticulum by retrieval from the ER-Golgi intermediate compartment
Objective
Phospholamban and sarcolipin are small transmembrane proteins that modulate cardiac contractility through their interaction with the sarcoplasmic reticulum (SR) calcium pumps (SERCAs). We have examined the hypothesis that phospholamban and sarcolipin are maintained in the SR by a process of retrieval from post-SR compartments and the role of their transmembrane domains in targeting.
Methods
Antibodies directed against phospholamban and protein markers of the endoplasmic reticulum/Golgi intermediate compartment (ERGIC) and the trans-Golgi were used in fluorescence microscopy studies of cultured human fetal cardiac myocytes. In addition, sarcolipin and phospholamban were tagged at the N-terminus with enhanced-green-fluorescent protein (EGFP) and expressed in COS 7 cells. The EGFP-tagged constructs were localised using fluorescence microscopy and cell fractionation. The length of the transmembrane domains of phospholamban and sarcolipin were extended and the effect on cellular location was also examined.
Results
In fetal cardiac myocytes phospholamban was located in the SR and the ERGIC, but did not migrate to the trans-Golgi network. Tagged-phospholamban and sarcolipin were located in the endoplasmic reticulum (ER) of COS 7 cells indicating that their targeting was unaffected by the EGFP tag. Significant proportions of the tagged phospholamban and sarcolipin were also located in the ERGIC but not in the trans-Golgi. Increasing the length of the transmembranous domains of EGFP-tagged phospholamban and sarcolipin resulted in their mis-targeting to the plasma membrane.
Conclusions
Phospholamban and sarcolipin are maintained in the SR/ER by a process that includes their retrieval from the ERGIC following their passage from the SR/ER into the ERGIC. The transmembrane domains of phospholamban and sarcolipin are involved in the retrieval process.
phospholamban, sarcolipin, targetting, endoplasmic reticulum, sarcoplasmic reticulum, retrieval, ERGIC, transmembrane domain
0008-6363
114-123
Butler, John
5132f0e2-f28d-412a-be9a-e97963b4c0ee
Lee, Anthony G.
0891914c-e0e2-4ee1-b43e-1b70eb072d8e
Wilson, David I.
1500fca1-7082-4271-95f4-691f1d1252a2
Spalluto, Cosma
6802ad50-bc38-404f-9a19-40916425183b
Hanley, Neil A.
bf03f7bb-f377-44fb-8344-0bb1ca8b2ef9
East, J. Malcolm
9fe7f794-1d89-4935-9a99-b831d786056e
Butler, John
5132f0e2-f28d-412a-be9a-e97963b4c0ee
Lee, Anthony G.
0891914c-e0e2-4ee1-b43e-1b70eb072d8e
Wilson, David I.
1500fca1-7082-4271-95f4-691f1d1252a2
Spalluto, Cosma
6802ad50-bc38-404f-9a19-40916425183b
Hanley, Neil A.
bf03f7bb-f377-44fb-8344-0bb1ca8b2ef9
East, J. Malcolm
9fe7f794-1d89-4935-9a99-b831d786056e

Butler, John, Lee, Anthony G., Wilson, David I., Spalluto, Cosma, Hanley, Neil A. and East, J. Malcolm (2007) Phospholamban and sarcolipin are maintained in the endoplasmic reticulum by retrieval from the ER-Golgi intermediate compartment. Cardiovascular Research, 74 (1), 114-123. (doi:10.1016/j.cardiores.2007.01.006).

Record type: Article

Abstract

Objective
Phospholamban and sarcolipin are small transmembrane proteins that modulate cardiac contractility through their interaction with the sarcoplasmic reticulum (SR) calcium pumps (SERCAs). We have examined the hypothesis that phospholamban and sarcolipin are maintained in the SR by a process of retrieval from post-SR compartments and the role of their transmembrane domains in targeting.
Methods
Antibodies directed against phospholamban and protein markers of the endoplasmic reticulum/Golgi intermediate compartment (ERGIC) and the trans-Golgi were used in fluorescence microscopy studies of cultured human fetal cardiac myocytes. In addition, sarcolipin and phospholamban were tagged at the N-terminus with enhanced-green-fluorescent protein (EGFP) and expressed in COS 7 cells. The EGFP-tagged constructs were localised using fluorescence microscopy and cell fractionation. The length of the transmembrane domains of phospholamban and sarcolipin were extended and the effect on cellular location was also examined.
Results
In fetal cardiac myocytes phospholamban was located in the SR and the ERGIC, but did not migrate to the trans-Golgi network. Tagged-phospholamban and sarcolipin were located in the endoplasmic reticulum (ER) of COS 7 cells indicating that their targeting was unaffected by the EGFP tag. Significant proportions of the tagged phospholamban and sarcolipin were also located in the ERGIC but not in the trans-Golgi. Increasing the length of the transmembranous domains of EGFP-tagged phospholamban and sarcolipin resulted in their mis-targeting to the plasma membrane.
Conclusions
Phospholamban and sarcolipin are maintained in the SR/ER by a process that includes their retrieval from the ERGIC following their passage from the SR/ER into the ERGIC. The transmembrane domains of phospholamban and sarcolipin are involved in the retrieval process.

This record has no associated files available for download.

More information

Published date: 2007
Additional Information: This paper describes the way in which the regulators of endoplasmic reticulum (ER) calcium pumps, phospholamban and sarcolipin, are maintained in the ER and prevented from entering the plasma membrane.
Keywords: phospholamban, sarcolipin, targetting, endoplasmic reticulum, sarcoplasmic reticulum, retrieval, ERGIC, transmembrane domain

Identifiers

Local EPrints ID: 44691
URI: http://eprints.soton.ac.uk/id/eprint/44691
ISSN: 0008-6363
PURE UUID: 55c2abfd-ee82-4ef0-ac43-4b0765e3363b
ORCID for Cosma Spalluto: ORCID iD orcid.org/0000-0001-7273-0844

Catalogue record

Date deposited: 16 Apr 2007
Last modified: 16 Mar 2024 03:24

Export record

Altmetrics

Contributors

Author: John Butler
Author: Anthony G. Lee
Author: David I. Wilson
Author: Cosma Spalluto ORCID iD
Author: Neil A. Hanley
Author: J. Malcolm East

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×