Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Multifaceted roles of the transmembrane nuclear envelope protein, Samp1
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.ORCID-id: 0000-0003-1287-0495
2017 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

The eukaryotic nuclear envelope (NE), separates the nucleoplasm from cytoplasm and is made up of two concentric lipid membranes, the outer and the inner nuclear membranes (ONM and INM), the nuclear pore complexes (NPCs) and an underlying filamentous nuclear lamina. The INM contains hundreds of unique transmembrane proteins of which only a handful have been characterized. In this thesis, I aimed to understand the functional organization of proteins in the nuclear envelope and I focused on investigating the functions of a recently identified INM transmembrane protein, Samp1. We have developed a novel and robust approach, MCLIP, to identify specific protein-protein interactions taking place in live cells. Using MCLIP, we have shown that Samp1 interacts with proteins of the LINC complex, the nuclear lamina and components of the mitotic spindle. Samp1's specific interactions with a variety of binding partners, suggest that Samp1 plays important roles both in interphase and in mitosis.  We have also shown that Samp1 can provide a binding site at the INM for the GTPase Ran, a master regulator of protein interactions in interphase and in mitosis. Furthermore, we have also investigated the role of Samp1 in cell differentiation using two independent model systems. In human iPSCs, ectopic expression of Samp1 promoted differentiation despite pluripotent culture conditions. In C2C12 myoblast, depletion of Samp1 completely blocked differentiation into myotubes. The two studies complement each other and suggest that Samp1 has a strong differentiation promoting activity. Taken together, the findings in this thesis, give insights on the unexpected and unforeseen roles played by a transmembrane protein in different fundamental cellular process.

sted, utgiver, år, opplag, sider
Stockholm: Department of Neurochemistry, Stockholm University , 2017. , s. 46
Emneord [en]
Nuclear envelope, transmembrane protein interaction studies, cell differentiation, stem cells, myopathies
HSV kategori
Forskningsprogram
neurokemi med molekylär neurobiologi
Identifikatorer
URN: urn:nbn:se:su:diva-141816ISBN: 978-91-7649-577-3 (tryckt)ISBN: 978-91-7649-578-0 (digital)OAI: oai:DiVA.org:su-141816DiVA, id: diva2:1089372
Disputas
2017-05-31, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (engelsk)
Opponent
Veileder
Merknad

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript. Paper 5: Manuscript.

Tilgjengelig fra: 2017-05-08 Laget: 2017-04-19 Sist oppdatert: 2018-06-19bibliografisk kontrollert
Delarbeid
1. MCLIP, an effective method to detect interactions of transmembrane proteins of the nuclear envelope in live cells
Åpne denne publikasjonen i ny fane eller vindu >>MCLIP, an effective method to detect interactions of transmembrane proteins of the nuclear envelope in live cells
Vise andre…
2014 (engelsk)Inngår i: Biochimica et Biophysica Acta - Biomembranes, ISSN 0005-2736, E-ISSN 1879-2642, Vol. 1838, nr 10, s. 2399-2403Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Investigating interactions of proteins in the nuclear envelope (NE) using co-immunoprecipitation (Co-IP) has previously been difficult or even impossible due to their inherent resistance to extraction. We have developed a novel method, MCLIP (Membrane protein Cross-Link ImmunoPrecipitation), which takes advantage of a cell permeable crosslinker to enable effective detection and analysis of specific interactions of NE proteins in live cells using Western blot. Using MCLIP we show that, in U2OS cells, the integral inner nuclear membrane protein Samp1 interacts with Lamin B1, the LINC (Linker of nucleoskeleton and cytoskeleton) complex protein, Sun1 and the soluble small GTPase Ran. The results show that the previously detected in vitro interaction between Samp1 and Emerin also takes place in live cells. In vitro pull down experiments show, that the nucleoplasmic domains of Samp1 and Emerin can bind directly to each other. We also, show that MCLIP is suitable to coprecipitate protein interactions in different stages of the cell cycle.

Emneord
Samp1, Nuclear envelope, Nuclear membrane, Crosslinking, CoIP, Protein–protein interaction
HSV kategori
Forskningsprogram
neurokemi med molekylär neurobiologi
Identifikatorer
urn:nbn:se:su:diva-109181 (URN)10.1016/j.bbamem.2014.06.008 (DOI)000340975600005 ()
Forskningsfinansiär
Swedish Research Council, 621-2010-448Swedish Cancer Society, 110590
Tilgjengelig fra: 2014-11-14 Laget: 2014-11-14 Sist oppdatert: 2018-03-20bibliografisk kontrollert
2. Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane
Åpne denne publikasjonen i ny fane eller vindu >>Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane
2016 (engelsk)Inngår i: Nucleus, ISSN 1949-1034, E-ISSN 1949-1042, Vol. 7, nr 4, s. 415-423Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

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.

Emneord
EDMD, laminopathies, LINC complex, nucleus, nuclear membrane, Ran
HSV kategori
Forskningsprogram
neurokemi med molekylär neurobiologi
Identifikatorer
urn:nbn:se:su:diva-135087 (URN)10.1080/19491034.2016.1220465 (DOI)000384442800010 ()27541860 (PubMedID)
Tilgjengelig fra: 2016-11-23 Laget: 2016-10-31 Sist oppdatert: 2017-10-30bibliografisk kontrollert
3. Mitotic spindle assembly and correct chromosome segregation depend on the integral nuclear membrane protein, Samp1
Åpne denne publikasjonen i ny fane eller vindu >>Mitotic spindle assembly and correct chromosome segregation depend on the integral nuclear membrane protein, Samp1
Vise andre…
(engelsk)Manuskript (preprint) (Annet vitenskapelig)
HSV kategori
Forskningsprogram
neurokemi med molekylär neurobiologi
Identifikatorer
urn:nbn:se:su:diva-141814 (URN)
Tilgjengelig fra: 2017-04-18 Laget: 2017-04-18 Sist oppdatert: 2017-10-30bibliografisk kontrollert
4. An inner nuclear membrane protein induces rapid differentiation of human induced pluripotent stem cells
Åpne denne publikasjonen i ny fane eller vindu >>An inner nuclear membrane protein induces rapid differentiation of human induced pluripotent stem cells
Vise andre…
(engelsk)Manuskript (preprint) (Annet vitenskapelig)
HSV kategori
Forskningsprogram
neurokemi med molekylär neurobiologi
Identifikatorer
urn:nbn:se:su:diva-135805 (URN)
Forskningsfinansiär
Swedish Research CouncilSwedish Cancer Society
Tilgjengelig fra: 2016-11-23 Laget: 2016-11-23 Sist oppdatert: 2017-04-27bibliografisk kontrollert
5. Spindle associated membrane protein 1 (Samp1) is required for the differentiation of muscle cells
Åpne denne publikasjonen i ny fane eller vindu >>Spindle associated membrane protein 1 (Samp1) is required for the differentiation of muscle cells
2017 (engelsk)Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikkel-id 16655Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Muscles are developed and regenerated in a differentiation process called myogenesis, which involves components of the nuclear envelope. We have investigated Samp1 (Spindle Associated Membrane Protein 1), a transmembrane nuclear envelope protein, which interacts with emerin and lamin A, both of which are linked to Emery-Dreifuss muscular dystrophy (EDMD). We found that the levels of Samp1 increased seven-fold during differentiation of mouse C2C12 muscle progenitor cells. To test if Samp1 could have a role in myogenesis we developed stable C2C12 knockdown cell lines expressing short hairpin RNA targeting Samp1 expression. The Samp1 depleted C2C12 cells displayed normal mobility and normal distribution of emerin and lamin A. However, Samp1 depletion increased ERK signaling and completely blocked differentiation of C2C12 cells, which failed to express myogenic marker proteins and failed to form myotubes. The block in myogenesis in Samp1 depleted cells was completely rescued by ectopic expression of RNAi resistant human Samp1, showing that Samp1 is required for muscle differentiation.

HSV kategori
Forskningsprogram
neurokemi med molekylär neurobiologi
Identifikatorer
urn:nbn:se:su:diva-150882 (URN)10.1038/s41598-017-16746-y (DOI)000416891400057 ()29192166 (PubMedID)
Tilgjengelig fra: 2018-01-10 Laget: 2018-01-10 Sist oppdatert: 2018-06-19bibliografisk kontrollert

Open Access i DiVA

Multifaceted roles of the transmembrane nuclear envelope protein, Samp1(1062 kB)88 nedlastinger
Filinformasjon
Fil FULLTEXT01.pdfFilstørrelse 1062 kBChecksum SHA-512
50dbc4395675a51c954861a717e8db955527ab2f179998417672230d4ecce4eb130690dac9829176ddfe85c89b8c281307fb99e3185a0893db7761085e5b0e3a
Type fulltextMimetype application/pdf
Errata_Multifaceted roles of the transmembrane nuclear envelope protein, Samp1(42 kB)14 nedlastinger
Filinformasjon
Fil ERRATA01.pdfFilstørrelse 42 kBChecksum SHA-512
9320915326f8dea9afefb2b09b7c91b7ff5f3aad7751a874769c9f1f63c304eaab122cc77ae5904cf1f1728b6504d3b2f7b6931ab44c70679a0b0b188992ca37
Type errataMimetype application/pdf

Søk i DiVA

Av forfatter/redaktør
Jaffer Ali, Mohammed Hakim
Av organisasjonen

Søk utenfor DiVA

GoogleGoogle Scholar
Totalt: 88 nedlastinger
Antall nedlastinger er summen av alle nedlastinger av alle fulltekster. Det kan for eksempel være tidligere versjoner som er ikke lenger tilgjengelige

isbn
urn-nbn

Altmetric

isbn
urn-nbn
Totalt: 664 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf