Cargando…

Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane

Samp1 is a transmembrane protein of the inner nuclear membrane (INM), which interacts with the nuclear lamina and the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex in interphase and during mitosis, it localizes to the mitotic spindle. Samp1 was recently found to coprecipitate a protein co...

Descripción completa

Detalles Bibliográficos
Autores principales: Vijayaraghavan, Balaje, Jafferali, Mohammed Hakim, Figueroa, Ricardo A., Hallberg, Einar
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Taylor & Francis 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5039005/
https://www.ncbi.nlm.nih.gov/pubmed/27541860
http://dx.doi.org/10.1080/19491034.2016.1220465
_version_ 1782455987539542016
author Vijayaraghavan, Balaje
Jafferali, Mohammed Hakim
Figueroa, Ricardo A.
Hallberg, Einar
author_facet Vijayaraghavan, Balaje
Jafferali, Mohammed Hakim
Figueroa, Ricardo A.
Hallberg, Einar
author_sort Vijayaraghavan, Balaje
collection PubMed
description Samp1 is a transmembrane protein of the inner nuclear membrane (INM), which interacts with the nuclear lamina and the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex in interphase and during mitosis, it localizes to the mitotic spindle. Samp1 was recently found to coprecipitate a protein complex containing Ran, a GTPase with fundamental regulatory functions both in interphase and in mitosis. To investigate the interaction between Samp1 and Ran in further detail, we have designed and expressed recombinant fusion proteins of the Chaetomium thermophilum homolog of Samp1 (Ct.Samp1) and human Ran. Pulldown experiments show that Samp1 binds directly to Ran and that Samp1 binds better to RanGTP compared to RanGDP. Samp1 also preferred RanGTP over RanGDP in living tsBN2 cells. We also show that the Ran binding domain is located between amino acids 75–135 in the nucleoplasmically exposed N-terminal tail of Samp1. This domain is unique for Samp1, without homology in any other proteins in fungi or metazoa. Samp1 is the first known transmembrane protein that binds to Ran and could provide a unique local binding site for RanGTP in the INM. Samp1 overexpression resulted in increased Ran concentrations in the nuclear periphery supporting this idea.
format Online
Article
Text
id pubmed-5039005
institution National Center for Biotechnology Information
language English
publishDate 2016
publisher Taylor & Francis
record_format MEDLINE/PubMed
spelling pubmed-50390052016-10-18 Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane Vijayaraghavan, Balaje Jafferali, Mohammed Hakim Figueroa, Ricardo A. Hallberg, Einar Nucleus Research Paper Samp1 is a transmembrane protein of the inner nuclear membrane (INM), which interacts with the nuclear lamina and the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex in interphase and during mitosis, it localizes to the mitotic spindle. Samp1 was recently found to coprecipitate a protein complex containing Ran, a GTPase with fundamental regulatory functions both in interphase and in mitosis. To investigate the interaction between Samp1 and Ran in further detail, we have designed and expressed recombinant fusion proteins of the Chaetomium thermophilum homolog of Samp1 (Ct.Samp1) and human Ran. Pulldown experiments show that Samp1 binds directly to Ran and that Samp1 binds better to RanGTP compared to RanGDP. Samp1 also preferred RanGTP over RanGDP in living tsBN2 cells. We also show that the Ran binding domain is located between amino acids 75–135 in the nucleoplasmically exposed N-terminal tail of Samp1. This domain is unique for Samp1, without homology in any other proteins in fungi or metazoa. Samp1 is the first known transmembrane protein that binds to Ran and could provide a unique local binding site for RanGTP in the INM. Samp1 overexpression resulted in increased Ran concentrations in the nuclear periphery supporting this idea. Taylor & Francis 2016-08-19 /pmc/articles/PMC5039005/ /pubmed/27541860 http://dx.doi.org/10.1080/19491034.2016.1220465 Text en © 2016 The Author(s). Published with license by Taylor & Francis. http://creativecommons.org/licenses/by-nc/3.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution-Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The moral rights of the named author(s) have been asserted.
spellingShingle Research Paper
Vijayaraghavan, Balaje
Jafferali, Mohammed Hakim
Figueroa, Ricardo A.
Hallberg, Einar
Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane
title Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane
title_full Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane
title_fullStr Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane
title_full_unstemmed Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane
title_short Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane
title_sort samp1, a rangtp binding transmembrane protein in the inner nuclear membrane
topic Research Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5039005/
https://www.ncbi.nlm.nih.gov/pubmed/27541860
http://dx.doi.org/10.1080/19491034.2016.1220465
work_keys_str_mv AT vijayaraghavanbalaje samp1arangtpbindingtransmembraneproteinintheinnernuclearmembrane
AT jafferalimohammedhakim samp1arangtpbindingtransmembraneproteinintheinnernuclearmembrane
AT figueroaricardoa samp1arangtpbindingtransmembraneproteinintheinnernuclearmembrane
AT hallbergeinar samp1arangtpbindingtransmembraneproteinintheinnernuclearmembrane