|
|
|
|
|
||
|
|||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | |||||
First published online 15 April 2003
doi: 10.1242/jcs.00424
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Research Article |
1 CNRS-UMR 5539, Université Montpellier 2, Place Eugène Bataillon,
34095 Montpellier Cedex 05, France
2 INSERM U563, CHU Purpan, place du Dr Blayac, 31059 Toulouse Cedex 03,
France
* Author for correspondence (e-mail: bettache{at}univ-montp2.fr)
Accepted 11 February 2003
Platelets were used to explore the effect of membrane curvature induced by phospholipid excess on cell shape and on organization of the actin cytoskeleton. We showed that the addition of short chain analogues of phospholipids to the outer leaflet of plasma membrane of resting platelets immediately induced a shape change with long filopodia formation containing newly polymerized actin. Cells recovered rapidly their discoid shape and their initial F-actin content only with the phosphatidylserine analogue, which was transported to the inner leaflet by aminophospholipid translocase. Filopodia formation and actin polymerization were inhibited in platelets pre-incubated with cytochalasin D. Both wortmannin and LY294002, two unrelated inhibitors of phosphoinositide 3-kinase, considerably reduced actin polymerization and filopodia formation. Phospholipid imbalance was accompanied by a reversible translocation of phosphoinositide 3-kinase from cytoplasm to plasma membrane. In agreement with a role for PI 3-kinase, when phospholipids were added to platelets, PtdIns(3,4)P2 increased two-fold and Akt protein was partly phosphorylated. A similar shape change was also observed in nocodazole-treated L929 fibroblasts which were incubated with the similar phospholipid analogues. In those nucleated cells, where the microtubule cytoskeleton was disrupted, a major actin-dependent membrane extension was induced by addition of short chain phospholipids that required the functional integrity of PI 3-kinase. We conclude that any physical constraint acting on plasma membrane and resulting on local changes in membrane curvature is sufficient to initiate transient actin polymerization via phosphoinositide 3-kinase activation.
Key words: Platelet, Phospholipid, Filopodia, Actin filament, PI 3-kinase, Akt, Fibroblast
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
This article has been cited by other articles:
|
|
 |
|
  D. Liebl and G. Griffiths Transient assembly of F-actin by phagosomes delays phagosome fusion with lysosomes in cargo-overloaded macrophages J. Cell Sci., August 15, 2009; 122(16): 2935 - 2945. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. C. Frasch, K. Zemski-Berry, R. C. Murphy, N. Borregaard, P. M. Henson, and D. L. Bratton Lysophospholipids of Different Classes Mobilize Neutrophil Secretory Vesicles and Induce Redundant Signaling through G2A J. Immunol., May 15, 2007; 178(10): 6540 - 6548. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Bodin and M. D. Welch Plasma Membrane Organization Is Essential for Balancing Competing Pseudopod- and Uropod-promoting Signals during Neutrophil Polarization and Migration Mol. Biol. Cell, December 1, 2005; 16(12): 5773 - 5783. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. A. Ferreira, A. I. M. Mocking, R. T. Urbanus, S. Varlack, M. Wnuk, and J.-W. N. Akkerman Glucose Uptake via Glucose Transporter 3 by Human Platelets Is Regulated by Protein Kinase B J. Biol. Chem., September 23, 2005; 280(38): 32625 - 32633. [Abstract] [Full Text] [PDF]
|
|
