PMID- 16816402
OWN - NLM
STAT- MEDLINE
DCOM- 20070329
LR  - 20210217
IS  - 0022-2275 (Print)
IS  - 0022-2275 (Linking)
VI  - 47
IP  - 10
DP  - 2006 Oct
TI  - Agrin elicits membrane lipid condensation at sites of acetylcholine receptor 
      clusters in C2C12 myotubes.
PG  - 2121-33
AB  - The formation of the neuromuscular junction is characterized by the progressive 
      accumulation of nicotinic acetylcholine receptors (AChRs) in the postsynaptic 
      membrane facing the nerve terminal, induced predominantly through the 
      agrin/muscle-specific kinase (MuSK) signaling cascade. However, the cellular 
      mechanisms linking MuSK activation to AChR clustering are still poorly 
      understood. Here, we investigate whether lipid rafts are involved in 
      agrin-elicited AChR clustering in a mouse C2C12 cell line. We observed that in 
      C2C12 myotubes, both AChR clustering and cluster stability were dependent on 
      cholesterol, because depletion by methyl-beta-cyclodextrin inhibited cluster 
      formation or dispersed established clusters. Importantly, AChR clusters resided 
      in ordered membrane domains, a biophysical property of rafts, as probed by 
      Laurdan two-photon fluorescence microscopy. We isolated detergent-resistant 
      membranes (DRMs) by three different biochemical procedures, all of which generate 
      membranes with similar cholesterol/GM1 ganglioside contents, and these were 
      enriched in several postsynaptic components, notably AChR, syntrophin, and raft 
      markers flotillin-2 and caveolin-3. Agrin did not recruit AChRs into DRMs, 
      suggesting that they are present in rafts independently of agrin activation. 
      Consequently, in C2C12 myotubes, agrin likely triggers AChR clustering or 
      maintains clusters through the coalescence of lipid rafts. These data led us to 
      propose a model in which lipid rafts play a pivotal role in the assembly of the 
      postsynaptic membrane at the neuromuscular junction upon agrin signaling.
FAU - Stetzkowski-Marden, Francoise
AU  - Stetzkowski-Marden F
AD  - Biologie Cellulaire des Membranes, Institut Jacques Monod, Unite Mixte de 
      Recherche 7592, Centre National de la Recherche Scientifique, Universite Paris 6, 
      Universite Paris 7, F-75251 Paris Cedex 05, France.
FAU - Gaus, Katharina
AU  - Gaus K
FAU - Recouvreur, Michel
AU  - Recouvreur M
FAU - Cartaud, Annie
AU  - Cartaud A
FAU - Cartaud, Jean
AU  - Cartaud J
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20060701
PL  - United States
TA  - J Lipid Res
JT  - Journal of lipid research
JID - 0376606
RN  - 0 (Agrin)
RN  - 0 (Membrane Lipids)
RN  - 0 (Receptors, Cholinergic)
SB  - IM
MH  - Agrin/*metabolism
MH  - Animals
MH  - Caveolae
MH  - Cell Line
MH  - Cell Membrane/*metabolism
MH  - Enzyme Activation
MH  - Lipid Metabolism
MH  - Membrane Lipids/*metabolism
MH  - Membrane Microdomains/metabolism
MH  - Mice
MH  - Models, Biological
MH  - Muscle Fibers, Skeletal/*metabolism
MH  - Neuromuscular Junction/metabolism
MH  - Receptors, Cholinergic/*metabolism
EDAT- 2006/07/04 09:00
MHDA- 2007/03/30 09:00
CRDT- 2006/07/04 09:00
PHST- 2006/07/04 09:00 [pubmed]
PHST- 2007/03/30 09:00 [medline]
PHST- 2006/07/04 09:00 [entrez]
AID - S0022-2275(20)43400-5 [pii]
AID - 10.1194/jlr.M600182-JLR200 [doi]
PST - ppublish
SO  - J Lipid Res. 2006 Oct;47(10):2121-33. doi: 10.1194/jlr.M600182-JLR200. Epub 2006 
      Jul 1.