Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Actin filaments at the plasma membrane in live cells cause the formation of ordered lipid domains via phosphatidylinositol 4,5-bisphosphate
Stockholm University, Faculty of Science, The Wenner-Gren Institute .
Uppsala universitet, Institutionen för medicinsk cellbiologi.
(English)In: Journal of Cell Science, ISSN 0021-9533, E-ISSN 1477-9137Article in journal (Refereed) Submitted
Abstract [en]

The relationship between ordered plasma membrane nanodomains, known as lipid rafts, and actin filaments is the focus of this study. Plasma membrane order was followed in live cells at 37°C using laurdan and di-4-ANEPPDHQ to report on lipid packing. Disrupting actin polymerization decreased the fraction of ordered domains, which strongly argue that unstimulated cells have a basal level of ordered domains. Stabilising actin filaments had the opposite effect and increased the proportion of ordered domains. Decreasing the plasma membrane level of phosphatidylinositol 4,5-bisphosphate lowers the number of attachment points for actin filaments and reduced the proportion of ordered domains. Aggregation of plasma membrane molecules, both lipid raft and non-lipid raft markers, leads to the formation of ordered domains that is correlated with an increase in cell peripheral actin filaments. In membrane blebs, which are detached from the underlying actin filaments the fraction of ordered domains was low and GM1 could not be patched to form ordered domains. We conclude that ordered domains form where actin filaments attach to the plasma membrane via phosphatidylinositol 4,5-bisphosphate. This downplays lipid-lipid interactions as the main driving force behind the formation of ordered membrane domains in vivo, giving greater prominence to membrane-intracellular filament interactions.

Keyword [en]
actin, generalised polarisation, laurdan, lipid rafts, liquid ordered phase, membrane order, phosphatidylinositol 4, 5-bisphosphate
National Category
Cell Biology
Research subject
Cellbiology
Identifiers
URN: urn:nbn:se:su:diva-62286OAI: oai:DiVA.org:su-62286DiVA: diva2:441170
Available from: 2011-09-14 Created: 2011-09-13 Last updated: 2017-12-08Bibliographically approved
In thesis
1. Plasma membrane order; the role of cholesterol and links to actin filaments:  
Open this publication in new window or tab >>Plasma membrane order; the role of cholesterol and links to actin filaments:  
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The connection between T cell activation, plasma membrane order and actin filament dynamics was the main focus of this study. Laurdan and di-4-ANEPPDHQ, membrane order sensing probes, were shown to report only on lipid packing rather than being influenced by the presence of membrane-inserted peptides justifying their use in membrane order studies. These dyes were used to follow plasma membrane order in live cells at 37°C. Disrupting actin filaments had a disordering effect while stabilizing actin filaments had an ordering effect on the plasma membrane, indicating there is a basal level of ordered domains in resting cells. Lowering PI(4,5)P2 levels decreased the proportion of ordered domains strongly suggesting that the connection of actin filaments to the plasma membrane is responsible for the maintaining the level of ordered membrane domains. Membrane blebs, which are detached from the underlying actin filaments, contained a low fraction of ordered domains. Aggregation of membrane components resulted in a higher proportion of ordered plasma membrane domains and an increase in cell peripheral actin polymerization. This strongly suggests that the attachment of actin filaments to the plasma membrane induces the formation of ordered domains. Limited cholesterol depletion with methyl-beta-cyclodextrin triggered peripheral actin polymerization. Cholesterol depleted cells showed an increase in plasma membrane order as a result of actin filament accumulation underneath the membrane. Moderate cholesterol depletion also induced membrane domain aggregation and activation of T cell signaling events. The T cell receptor (TCR) aggregation caused redistribution of domains resulting in TCR patches of higher order and the bulk membrane correspondingly depleted of ordered domains. This suggests the preexistence of small ordered membrane domains in resting T cells that aggregate upon cell activation. Increased actin polymerization at the TCR aggregation sites showed that actin polymerization is strongly correlated with the changes in the distribution of ordered domains. The distribution of the TCR in resting cells and its colocalization with actin filaments is cell cycle dependent. We conclude that actin filament attachment to the plasma membrane, which is regulated via PI(4,5)P2, plays a crucial role in the formation of ordered domains.

Place, publisher, year, edition, pages
Stockholm: The Wenner-Gren Institute, Stockholm University, 2011. 56 p.
Keyword
Membrane Organization, Lipid rafts, Actin, Laurdan, di-4-ANEPPDHQ, Cholesterol, T cell signaling, Colocalization, Generalized Polarization
National Category
Cell Biology
Research subject
Cellbiology
Identifiers
urn:nbn:se:su:diva-62279 (URN)978-91-7447-365-0 (ISBN)
Public defence
2011-10-14, E306, Arrheniuslaboratorierna, Svante Arrhenius väg 20 C, Stockholm, 10:00 (English)
Opponent
Supervisors
Note
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 4: Manuscript. Available from: 2011-09-22 Created: 2011-09-13 Last updated: 2011-09-16Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Dinic, Jelena
By organisation
The Wenner-Gren Institute
In the same journal
Journal of Cell Science
Cell Biology

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 82 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf