A: Immunoblot with mAb 210 (monoclonal antibody against the α
subunit of the T. californica AChR) of DRM (P) and DSM
(S) fractions obtained from purified AChR reconstituted in POPC:SM:Chol
containing GM1 (i) without further treatment, (ii) treated with cholera
toxin B subunit (CTxB) for GM1 crosslinking, and (iii) treated with CTxB
for GM1 crosslinking followed by anti-cholera toxin antibody (anti-CTx)
for crosslinking of CTxB. B: Immunoblot of DSM (S) and DRM (P) fractions
obtained from purified AChR reconstituted in a POPC:SM:Chol 1:1:1 system
in the presence of a rapsyn-enriched extract in three different
rapsyn:AChR molar stoichiometries (1:1, 2:1, and 4:1). Blots were probed
with mAb 1234 (monoclonal antibody against rapsyn) and mAb 210
(monoclonal antibody against the α subunit of the T.
californica AChR). Panels A and B are representative of at
least three independent experiments. AChR, nicotinic acetylcholine
receptor; Chol, cholesterol; CTx, cholera toxin; CTxB, cholera toxin
B-subunit; DRM, detergent-resistant membrane; DSM, detergent-soluble
membrane; GM1, ganglioside GM1; POPC, palmitoyloleylphosphatydilcholine;
SM, brain sphingomyelin.